Nucleic acid encoding cytokine receptor zcytor17

ABSTRACT

Novel polypeptides, polynucleotides encoding the polypeptides, and related compositions and methods are disclosed for zcytor17, a novel cytokine receptor. The polypeptides may be used within methods for detecting ligands that stimulate the proliferation and/or development of hematopoietic, lymphoid and myeloid cells in vitro and in vivo. Ligand-binding receptor polypeptides can also be used to block ligand activity in vitro and in vivo. The polynucleotides encoding zcytor17, are located on chromosome 5, and can be used to identify a region of the genome associated with human disease states. The present invention also includes methods for producing the protein, uses therefor and antibodies thereto.

The present invention is a continuation of U.S. patent application Ser.No. 09/892,949, filed Jun. 26, 2001, which claims the benefit of U.S.Patent Application Ser. Nos. 60/267,963, filed Feb. 8, 2001, 60/214,955,filed Jun. 29, 2000, and 60/214,282, filed Jun. 26, 2000, all of whichare herein incorporated by reference.

BACKGROUND OF THE INVENTION

Hormones and polypeptide growth factors control proliferation anddifferentiation of cells of multicellular organisms. These diffusablemolecules allow cells to communicate with each other and act in concertto form cells and organs, and to repair damaged tissue. Examples ofhormones and growth factors include the steroid hormones (e.g. estrogen,testosterone), parathyroid hormone, follicle stimulating hormone, theinterleukins, platelet derived growth factor (PDGF), epidermal growthfactor (EGF), granulocyte-macrophage colony stimulating factor (GM-CSF),erythropoietin (EPO) and calcitonin.

Hormones and growth factors influence cellular metabolism by binding toreceptors. Receptors may be integral membrane proteins that are linkedto signaling pathways within the cell, such as second messenger systems.Other classes of receptors are soluble molecules, such as thetranscription factors. Of particular interest are receptors forcytokines, molecules that promote the proliferation and/ordifferentiation of cells. Examples of cytokines include erythropoietin(EPO), which stimulates the development of red blood cells;thrombopoietin (TPO), which stimulates development of cells of themegakaryocyte lineage; and granulocyte-colony stimulating factor(G-CSF), which stimulates development of neutrophils. These cytokinesare useful in restoring normal blood cell levels in patients sufferingfrom anemia, thrombocytopenia, and neutropenia or receiving chemotherapyfor cancer.

The demonstrated in vivo activities of these cytokines illustrate theenormous clinical potential of, and need for, other cytokines, cytokineagonists, and cytokine antagonists. The present invention addressesthese needs by providing new a hematopoietic cytokine receptor, as wellas related compositions and methods.

The present invention provides such polypeptides for these and otheruses that should be apparent to those skilled in the art from theteachings herein. These and other aspects of the invention will becomeevident upon reference to the following detailed description of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is depicted in 3 panels (FIG. A, FIG. 1B and FIG. 1C) and shows amultiple alignment of zcytor17 polynucleotide sequences SEQ ID NO:46,SEQ ID NO:18, SEQ ID NO:54, SEQ ID NO:2, and SEQ ID NO:22.

DESCRIPTION OF THE INVENTION

Within one aspect, the present invention provides an isolatedpolynucleotide that encodes a polypeptide comprising a sequence of aminoacid residues that is at least 90% identical to an amino acid sequenceselected from the group consisting of: (a) the amino acid sequence asshown in SEQ ID NO:2 from amino acid number 20 (Ala) to amino acidnumber 227 (Pro); (b) the amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to amino acid number 519 (Glu); (c) theamino acid sequence as shown in SEQ ID NO:2 from amino acid number 20(Ala) to amino acid number 543 (Leu); (d) the amino acid sequence asshown in SEQ ID NO:2 from amino acid number 544 (Lys) to amino acidnumber 732 (Val); (e) the amino acid sequence as shown in SEQ ID NO:46from amino acid number 544 (Lys) to amino acid number 649 (Ile); (f) theamino acid sequence as shown in SEQ ID NO:2 from amino acid number 20(Ala) to amino acid number 732 (Val); (g) the amino acid sequence asshown in SEQ ID NO:46 from amino acid number 20 (Ala) to amino acidnumber 649 (Ile); (h) the amino acid sequence as shown in SEQ ID NO:2from amino acid number 1 (Met) to amino acid number 732 (Val); and (i)the amino acid sequence as shown in SEQ ID NO:46 from amino acid number1 (Met) to amino acid number 649 (Ile). In one embodiment, the isolatedpolynucleotide disclosed above comprises a sequence of amino acidresidues that is selected from the group consisting of: (a) the aminoacid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Ala) toamino acid number 227 (Pro); (b) the amino acid sequence as shown in SEQID NO:2 from amino acid number 20 (Ala) to amino acid number 519 (Glu);(c) the amino acid sequence as shown in SEQ ID NO:2 from amino acidnumber 20 (Ala) to amino acid number 543 (Leu); (d) the amino acidsequence as shown in SEQ ID NO:2 from amino acid number 544 (Lys) toamino acid number 732 (Val); (e) the amino acid sequence as shown in SEQID NO:46 from amino acid number 544 (Lys) to amino acid number 649(Ile); (f) the amino acid sequence as shown in SEQ ID NO:2 from aminoacid number 20 (Ala) to amino acid number 732 (Val); (g) the amino acidsequence as shown in SEQ ID NO:46 from amino acid number 20 (Ala) toamino acid number 649 (Ile); (h) the amino acid sequence as shown in SEQID NO:2 from amino acid number 1 (Met) to amino acid number 732 (Val);and (i) the amino acid sequence as shown in SEQ ID NO:46 from amino acidnumber 1 (Met) to amino acid number 649 (Ile). In another embodiment,the isolated polynucleotide disclosed above comprises a sequenceselected from the group consisting of: (a) a polynucleotide as shown inSEQ ID NO: 1 from nucleotide number 228 to amino acid number 851; (b) apolynucleotide as shown in SEQ ID NO:1 from nucleotide number 228 toamino acid number 1727; (c) a polynucleotide as shown in SEQ ID NO:1from nucleotide number 228 to amino acid number 1799; (d) apolynucleotide as shown in SEQ ID NO:1 from nucleotide number 1800 toamino acid number 2366; (e) a polynucleotide as shown in SEQ ID NO:45from nucleotide number 1791 to amino acid number 2108; (f) apolynucleotide as shown in SEQ ID NO:1 from nucleotide number 228 toamino acid number 2366; (g) a polynucleotide as shown in SEQ ID NO:45from nucleotide number 219 to amino acid number 2108; (h) apolynucleotide as shown in SEQ ID NO:1 from nucleotide number 171 toamino acid number 2366; (i) a polynucleotide as shown in SEQ ID NO:45from nucleotide number 162 to amino acid number 2108; and (j) apolynucleotide sequence complementary to (a) through (i). In anotherembodiment, the isolated polynucleotide disclosed above encodes apolypeptide that further comprises a transmembrane domain consisting ofresidues 520 (Ile) to 543 (Leu) of SEQ ID NO:2. In another embodiment,the isolated polynucleotide disclosed above encodes a polypeptide thatfurther comprises an intracellular domain consisting of residues 544(Lys) to 732 (Val) of SEQ ID NO:2 or 544 (Lys) to 649 (Ile) of SEQ IDNO:46. In another embodiment, the isolated polynucleotide disclosedabove encodes a polypeptide that has activity as measured by cellproliferation, activation of transcription of a reporter gene, orwherein the polypeptide encoded by the polynucleotide further binds toan antibody, wherein the antibody is raised to a polypeptide comprisinga sequence of amino acids from the group consisting of: (a) thepolypeptide comprising amino acid number 20 (Ala) to 227 (Pro) of SEQ IDNO:2; (b) the polypeptide comprising amino acid number 20 (Ala) to 519(Glu) of SEQ ID NO:2; (c) the polypeptide comprising amino acid number20 (Ala) to 543 (Leu) of SEQ ID NO:2; (d) the polypeptide comprisingamino acid number 544 (Lys) to 732 (Val) of SEQ ID NO:2; (e) thepolypeptide comprising amino acid number 544 (Lys) to 649 (Ile) of SEQID NO:46; (f) the polypeptide comprising amino acid number 20 (Ala) to732 (Val) of SEQ ID NO:2; (g) the polypeptide comprising amino acidnumber 20 (Ala) to 649 (Ile) of SEQ ID NO:46; (h) the polypeptidecomprising amino acid number 1 (Met) to 732 (Val) of SEQ ID NO:2; and(i) the polypeptide comprising amino acid number 1 (Met) to 649 (Ile) ofSEQ ID NO:46, and wherein the binding of the antibody to the isolatedpolypeptide is measured by a biological or biochemical assay includingradioimmunoassay, radioimmuno-precipitation, Western blot, orenzyme-linked immunosorbent assay.

Within a second aspect, the present invention provides an expressionvector comprising the following operably linked elements: atranscription promoter; a DNA segment encoding a polypeptide that is atleast 90% identical to an amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to 732 (Val); or is at least 90%identical to an amino acid sequence as shown in SEQ ID NO:46 from aminoacid number 20 (Ala) to 649 (Ile); and a transcription terminator,wherein the promoter is operably linked to the DNA segment, and the DNAsegment is operably linked to the transcription terminator. In oneembodiment, the expression vector disclosed above further comprises asecretory signal sequence operably linked to the DNA segment.

Within a third aspect, the present invention provides a cultured cellcomprising an expression vector as disclosed above, wherein the cellexpresses a polypeptide encoded by the DNA segment. In anotherembodiment, the expression vector disclosed above comprises a DNAsegment that encodes a polypeptide comprising an amino acid sequence asshown in SEQ ID NO:2 from amino acid number 20 (Ala) to 227 (Pro); or asshown in SEQ ID NO:2 from amino acid number 20 (Ala) to 519 (Glu); and atranscription terminator, wherein the promoter, DNA segment, andterminator are operably linked. In another embodiment, the expressionvector disclosed above further comprises a secretory signal sequenceoperably linked to the DNA segment. In another embodiment, theexpression vector disclosed above further comprises a transmembranedomain consisting of residues 520 (Ile) to 543 (Leu) of SEQ ID NO:2. Inanother embodiment, the expression vector disclosed above furthercomprises an intracellular domain consisting of residues 544 (Lys) to732 (Val) of SEQ ID NO:2, or residues 544 (Lys) to 649 (Ile) of SEQ IDNO:46.

Within another aspect, the present invention provides a cultured cellinto which has been introduced an expression vector as disclosed above,wherein the cell expresses a soluble receptor polypeptide encoded by theDNA segment.

Within another aspect, the present invention provides a DNA constructencoding a fusion protein, the DNA construct comprising: a first DNAsegment encoding a polypeptide comprising a sequence of amino acidresidues selected from the group consisting of: (a) the amino acidsequence of SEQ ID NO:2 from amino acid number 1 (Met), to amino acidnumber 19 (Ala); (b) the amino acid sequence of SEQ ID NO:54 from aminoacid number 1 (Met), to amino acid number 32 (Ala); (c) the amino acidsequence of SEQ ID NO:2 from amino acid number 20 (Ala), to amino acidnumber 227 (Pro); (d) the amino acid sequence of SEQ ID NO:2 from aminoacid number 20 (Ala), to amino acid number 519 (Glu); (e) the amino acidsequence as shown in SEQ ID NO:2 from amino acid number 20 (Ala) toamino acid number 543 (Leu); (f) the amino acid sequence as shown in SEQID NO:2 from amino acid number 520 (Ile) to amino acid number 543 (Leu);(g) the amino acid sequence as shown in SEQ ID NO:2 from amino acidnumber 544 (Lys) to amino acid number 732 (Val); (h) the amino acidsequence as shown in SEQ ID NO:46 from amino acid number 544 (Lys) toamino acid number 649 (lie); (i) the amino acid sequence as shown in SEQID NO:2 from amino acid number 20 (Ala) to amino acid number 732 (Val);and (j) the amino acid sequence as shown in SEQ ID NO:46 from amino acidnumber 20 (Ala) to amino acid number 649 (Ile); and at least one otherDNA segment encoding an additional polypeptide, wherein the first andother DNA segments are connected in-frame; and wherein the first andother DNA segments encode the fusion protein.

Within another aspect, the present invention provides an expressionvector comprising the following operably linked elements: atranscription promoter; a DNA construct encoding a fusion protein asdisclosed above; and a transcription terminator, wherein the promoter isoperably linked to the DNA construct, and the DNA construct is operablylinked to the transcription terminator.

Within another aspect, the present invention provides a cultured cellcomprising an expression vector as disclosed above, wherein the cellexpresses a polypeptide encoded by the DNA construct.

Within another aspect, the present invention provides a method ofproducing a fusion protein comprising: culturing a cell as disclosedabove; and isolating the polypeptide produced by the cell.

Within another aspect, the present invention provides an isolatedpolypeptide comprising a sequence of amino acid residues that is atleast 90% identical to an amino acid sequence selected from the groupconsisting of: (a) the amino acid sequence as shown in SEQ ID NO:2 fromamino acid number 20 (Ala) to amino acid number 227 (Pro); (b) the aminoacid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Ala) toamino acid number 519 (Glu); (c) the amino acid sequence as shown in SEQID NO:2 from amino acid number 20 (Ala) to amino acid number 543 (Leu);(d) the amino acid sequence as shown in SEQ ID NO:2 from amino acidnumber 544 (Lys) to amino acid number 732 (Val); (e) the amino acidsequence as shown in SEQ ID NO:46 from amino acid number 544 (Lys) toamino acid number 649 (Ile); (f) the amino acid sequence as shown in SEQID NO:2 from amino acid number 20 (Ala) to amino acid number 732 (Val);(g) the amino acid sequence as shown in SEQ ID NO:46 from amino acidnumber 20 (Ala) to amino acid number 649 (Ile); (h) the amino acidsequence as shown in SEQ ID NO:2 from amino acid number 1 (Met) to aminoacid number 732 (Val); and (i) the amino acid sequence as shown in SEQID NO:46 from amino acid number 1 (Met) to amino acid number 649 (Ile).In one embodiment, the isolated polypeptide disclosed above comprises asequence of amino acid residues that is selected from the groupconsisting of: (a) the amino acid sequence as shown in SEQ ID NO:2 fromamino acid number 20 (Ala) to amino acid number 227 (Pro); (b) the aminoacid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Ala) toamino acid number 519 (Glu); (c) the amino acid sequence as shown in SEQID NO:2 from amino acid number 20 (Ala) to amino acid number 543 (Leu);(d) the amino acid sequence as shown in SEQ ID NO:2 from amino acidnumber 544 (Lys) to amino acid number 732 (Val); (e) the amino acidsequence as shown in SEQ ID NO:46 from amino acid number 544 (Lys) toamino acid number 649 (Ile); (f) the amino acid sequence as shown in SEQID NO:2 from amino acid number 20 (Ala) to amino acid number 732 (Val);(g) the amino acid sequence as shown in SEQ ID NO:46 from amino acidnumber 20 (Ala) to amino acid number 649 (Ile); (h) the amino acidsequence as shown in SEQ ID NO:2 from amino acid number 1 (Met) to aminoacid number 732 (Val); and (i) the amino acid sequence as shown in SEQID NO:46 from amino acid number 1 (Met) to amino acid number 649 (Ile).In another embodiment, the isolated polypeptide disclosed above furthercomprises a transmembrane domain consisting of residues 520 (Ile) to 543(Leu) of SEQ ID NO:2. In another embodiment, the isolated polypeptidedisclosed above further comprises an intracellular domain consisting ofresidues 544 (Lys) to 732 (Val) of SEQ ID NO:2 or 544 (Lys) to 649 (Ile)of SEQ ID NO:46. In another embodiment, the isolated polypeptidedisclosed above has activity as measured by cell proliferation,activation of transcription of a reporter gene, or wherein thepolypeptide encoded by the polynucleotide further binds to an antibody,wherein the antibody is raised to a polypeptide comprising a sequence ofamino acids from the group consisting of: (a) the polypeptide comprisingamino acid number 20 (Ala) to 227 (Pro) of SEQ ID NO:2; (b) thepolypeptide comprising amino acid number 20 (Ala) to 519 (Glu) of SEQ IDNO:2; (c) the polypeptide comprising amino acid number 20 (Ala) to 543(Leu) of SEQ ID NO:2; (d) the polypeptide comprising amino acid number544 (Lys) to 732 (Val) of SEQ ID NO:2; (e) the polypeptide comprisingamino acid number 544 (Lys) to 649 (Ile) of SEQ ID NO:46; (f) thepolypeptide comprising amino acid number 20 (Ala) to 732 (Val) of SEQ IDNO:2; (g) the polypeptide comprising amino acid number 20 (Ala) to 649(Ile) of SEQ ID NO:46; (h) the polypeptide comprising amino acid number1 (Met) to 732 (Val) of SEQ ID NO:2; and (i) the polypeptide comprisingamino acid number 1 (Met) to 649 (Ile) of SEQ ID NO:46, and wherein thebinding of the antibody to the isolated polypeptide is measured by abiological or biochemical assay including radioimmunoassay,radioimmuno-precipitation, Western blot, or enzyme-linked immunosorbentassay.

Within another aspect, the present invention provides a method ofproducing a zcytor17 polypeptide comprising: culturing a cell asdisclosed above; and isolating the zcytor17 polypeptide produced by thecell.

Within another aspect, the present invention provides an isolatedpolypeptide comprising an amino acid segment selected from the groupconsisting of: (a) the amino acid sequence as shown in SEQ ID NO:2 fromamino acid number 20 (Ala) to amino acid number 227 (Pro); (b) the aminoacid sequence as shown in SEQ ID NO:2 from amino acid number 20 (Ala) toamino acid number 519 (Glu); the amino acid sequence as shown in SEQ IDNO:18; the amino acid sequence as shown in SEQ ID NO:22; and (b)sequences that are at least 90% identical to (a) or (b), wherein thepolypeptide is substantially free of transmembrane and intracellulardomains ordinarily associated with hematopoietic receptors. Withinanother aspect, the present invention provides a method of producing azcytor17 polypeptide comprising: culturing a cell as disclosed above;and isolating the zcytor17 polypeptide produced by the cell. Withinanother aspect, the present invention provides a method of producing anantibody to a zcytor17 polypeptide comprising: inoculating an animalwith a polypeptide selected from the group consisting of: (a) apolypeptide consisting of 9 to 713 amino acids, wherein the polypeptidecomprises a contiguous sequence of amino acids in SEQ ID NO:2 from aminoacid number 20 (Ala), to amino acid number 732 (Val); (b) a polypeptideconsisting of 9 to 630 amino acids, wherein the polypeptide comprises acontiguous sequence of amino acids in SEQ ID NO:46 from amino acidnumber 20 (Ala), to amino acid number 649 (Ile); (c) a polypeptidecomprising amino acid number 20 (Ala) to 227 (Pro) of SEQ ID NO:2; (d) apolypeptide comprising amino acid number 20 (Ala) to 519 (Glu) of SEQ IDNO:2; (e) a polypeptide comprising amino acid number 20 (Ala) to 543(Leu) of SEQ ID NO:2; (f) a polypeptide comprising amino acid number 544(Lys) to 732 (Val) of SEQ ID NO:2; (g) a polypeptide comprising aminoacid number 544 (Lys) to 649 (Ile) of SEQ ID NO:46; (h) a polypeptidecomprising amino acid number 20 (Ala) to 732 (Val) of SEQ ID NO:2; (i) apolypeptide comprising amino acid number 20 (Ala) to 649 (Ile) of SEQ IDNO:46; (j) a polypeptide comprising amino acid number 1 (Met) to 732(Val) of SEQ ID NO:2; (k) a polypeptide comprising amino acid number 1(Met) to 649 (Ile) of SEQ ID NO:46, (1) a polypeptide comprising aminoacid residues 43 through 48 of SEQ ID NO:2; (m) a polypeptide comprisingamino acid residues 157 through 162 of SEQ ID NO:2; (n) a polypeptidecomprising amino acid residues 158 through 163 of SEQ ID NO:2; (o) apolypeptide comprising amino acid residues 221 through 226 of SEQ IDNO:2; and (p) a polypeptide comprising amino acid residues 426 through431 of SEQ ID NO:2; and wherein the polypeptide elicits an immuneresponse in the animal to produce the antibody; and isolating theantibody from the animal. Within another aspect, the present inventionprovides an antibody produced by the method as disclosed above, whichspecifically binds to a zcytor17 polypeptide. In one embodiment, theantibody disclosed above is a monoclonal antibody.

Within another aspect, the present invention provides an antibody thatspecifically binds to a polypeptide as disclosed above. In oneembodiment, the antibody disclosed above binds to a polypeptide of asdisclosed above.

Within another aspect, the present invention provides a method ofdetecting, in a test sample, the presence of a modulator of zcytor17protein activity, comprising: culturing a cell into which has beenintroduced an expression vector as disclosed above, wherein the cellexpresses the zcytor17 protein encoded by the DNA segment in thepresence and absence of a test sample; and comparing levels of activityof zcytor17 in the presence and absence of a test sample, by abiological or biochemical assay; and determining from the comparison,the presence of modulator of zcytor17 activity in the test sample.

Within another aspect, the present invention provides a method fordetecting a zcytor17 receptor ligand within a test sample, comprising:contacting a test sample with a polypeptide comprising an amino acidsequence from the group consisting of: (a) the amino acid sequence asshown in SEQ ID NO:2 from amino acid number 20 (Ala) to amino acidnumber 227 (Pro); (b) the amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to amino acid number 519 (Glu); theamino acid sequence as shown in SEQ ID NO:18; the amino acid sequence asshown in SEQ ID NO:22; and detecting the binding of the polypeptide to aligand in the sample. In one embodiment is provided the method disclosedabove wherein the polypeptide is membrane bound within a cultured cell,and the detecting step comprises measuring a biological response in thecultured cell. In another embodiment is provided the method disclosedabove wherein the biological response is cell proliferation oractivation of transcription of a reporter gene.

Prior to setting forth the invention in detail, it may be helpful to theunderstanding thereof to define the following terms:

The term “affinity tag” is used herein to denote a polypeptide segmentthat can be attached to a second polypeptide to provide for purificationor detection of the second polypeptide or provide sites for attachmentof the second polypeptide to a substrate. In principal, any peptide orprotein for which an antibody or other specific binding agent isavailable can be used as an affinity tag. Affinity tags include apoly-histidine tract, protein A (Nilsson et al., EMBO J. 4:1075, 1985;Nilsson et al., Methods Enzymol. 198:3, 1991), glutathione S transferase(Smith and Johnson, Gene 67:31, 1988), Glu-Glu affinity tag(Grussenmeyer et al., Proc. Natl. Acad. Sci. USA 82:7952-4, 1985),substance P, Flag™ peptide (Hopp et al., Biotechnology 6:1204-10, 1988),streptavidin binding peptide, or other antigenic epitope or bindingdomain. See, in general, Ford et al., Protein Expression andPurification 2: 95-107, 1991. DNAs encoding affinity tags are availablefrom commercial suppliers (e.g., Pharmacia Biotech, Piscataway, N.J.).

The term “allelic variant” is used herein to denote any of two or morealternative forms of a gene occupying the same chromosomal locus.Allelic variation arises naturally through mutation, and may result inphenotypic polymorphism within populations. Gene mutations can be silent(no change in the encoded polypeptide) or may encode polypeptides havingaltered amino acid sequence. The term allelic variant is also usedherein to denote a protein encoded by an allelic variant of a gene.

The terms “amino-terminal” and “carboxyl-terminal” are used herein todenote positions within polypeptides. Where the context allows, theseterms are used with reference to a particular sequence or portion of apolypeptide to denote proximity or relative position. For example, acertain sequence positioned carboxyl-terminal to a reference sequencewithin a polypeptide is located proximal to the carboxyl terminus of thereference sequence, but is not necessarily at the carboxyl terminus ofthe complete polypeptide.

The term “complement/anti-complement pair” denotes non-identicalmoieties that form a non-covalently associated, stable pair underappropriate conditions. For instance, biotin and avidin (orstreptavidin) are prototypical members of a complement/anti-complementpair. Other exemplary complement/anti-complement pairs includereceptor/ligand pairs, antibody/antigen (or hapten or epitope) pairs,sense/antisense polynucleotide pairs, and the like. Where subsequentdissociation of the complement/anti-complement pair is desirable, thecomplement/anti-complement pair preferably has a binding affinity of<10⁹ M⁻¹.

The term “complements of a polynucleotide molecule” is a polynucleotidemolecule having a complementary base sequence and reverse orientation ascompared to a reference sequence. For example, the sequence 5′ ATGCACGGG3′ is complementary to 5′ CCCGTGCAT 3′.

The term “contig” denotes a polynucleotide that has a contiguous stretchof identical or complementary sequence to another polynucleotide.Contiguous sequences are said to “overlap” a given stretch ofpolynucleotide sequence either in their entirety or along a partialstretch of the polynucleotide. For example, representative contigs tothe polynucleotide sequence 5′-ATGGCTTAGCTT-3′ are 5′-TAGCTTgagtct-3′and 3′-gtcgacTACCGA-5′.

The term “degenerate nucleotide sequence” denotes a sequence ofnucleotides that includes one or more degenerate codons (as compared toa reference polynucleotide molecule that encodes a polypeptide).Degenerate codons contain different triplets of nucleotides, but encodethe same amino acid residue (i.e., GAU and GAC triplets each encodeAsp).

The term “expression vector” is used to denote a DNA molecule, linear orcircular, that comprises a segment encoding a polypeptide of interestoperably linked to additional segments that provide for itstranscription. Such additional segments include promoter and terminatorsequences, and may also include one or more origins of replication, oneor more selectable markers, an enhancer, a polyadenylation signal, etc.Expression vectors are generally derived from plasmid or viral DNA, ormay contain elements of both.

The term “isolated”, when applied to a polynucleotide, denotes that thepolynucleotide has been removed from its natural genetic milieu and isthus free of other extraneous or unwanted coding sequences, and is in aform suitable for use within genetically engineered protein productionsystems. Such isolated molecules are those that are separated from theirnatural environment and include cDNA and genomic clones. Isolated DNAmolecules of the present invention are free of other genes with whichthey are ordinarily associated, but may include naturally occurring 5′and 3′ untranslated regions such as promoters and terminators. Theidentification of associated regions will be evident to one of ordinaryskill in the art (see for example, Dynan and Tijan, Nature 316:774-78,1985).

An “isolated” polypeptide or protein is a polypeptide or protein that isfound in a condition other than its native environment, such as apartfrom blood and animal tissue. In a preferred form, the isolatedpolypeptide is substantially free of other polypeptides, particularlyother polypeptides of animal origin. It is preferred to provide thepolypeptides in a highly purified form, i.e. greater than 95% pure, morepreferably greater than 99% pure. When used in this context, the term“isolated” does not exclude the presence of the same polypeptide inalternative physical forms, such as dimers, multimers, or alternativelyglycosylated or derivatized forms.

The term “operably linked”, when referring to DNA segments, indicatesthat the segments are arranged so that they function in concert fortheir intended purposes, e.g., transcription initiates in the promoterand proceeds through the coding segment to the terminator.

The term “ortholog” denotes a polypeptide or protein obtained from onespecies that is the functional counterpart of a polypeptide or proteinfrom a different species. Sequence differences among orthologs are theresult of speciation. “Paralogs” are distinct but structurally relatedproteins made by an organism. Paralogs are believed to arise throughgene duplication. For example, αX-globin, β-globin, and myoglobin areparalogs of each other.

A “polynucleotide” is a single- or double-stranded polymer ofdeoxyribonucleotide or ribonucleotide bases read from the 5′ to the 3′end. Polynucleotides include RNA and DNA, and may be isolated fromnatural sources, synthesized in vitro, or prepared from a combination ofnatural and synthetic molecules. Sizes of polynucleotides are expressedas base pairs (abbreviated “bp”), nucleotides (“nt”), or kilobases(“kb”). Where the context allows, the latter two terms may describepolynucleotides that are single-stranded or double-stranded. When theterm is applied to double-stranded molecules it is used to denoteoverall length and will be understood to be equivalent to the term “basepairs”. It will be recognized by those skilled in the art that the twostrands of a double-stranded polynucleotide may differ slightly inlength and that the ends thereof may be staggered as a result ofenzymatic cleavage; thus all nucleotides within a double-strandedpolynucleotide molecule may not be paired.

A “polypeptide” is a polymer of amino acid residues joined by peptidebonds, whether produced naturally or synthetically. Polypeptides of lessthan about 10 amino acid residues are commonly referred to as“peptides”.

“Probes and/or primers” as used herein can be RNA or DNA. DNA can beeither cDNA or genomic DNA. Polynucleotide probes and primers are singleor double-stranded DNA or RNA, generally synthetic oligonucleotides, butmay be generated from cloned cDNA or genomic sequences or itscomplements. Analytical probes will generally be at least 20 nucleotidesin length, although somewhat shorter probes (14-17 nucleotides) can beused. PCR primers are at least 5 nucleotides in length, preferably 15 ormore nt, more preferably 20-30 nt. Short polynucleotides can be usedwhen a small region of the gene is targeted for analysis. For grossanalysis of genes, a polynucleotide probe may comprise an entire exon ormore. Probes can be labeled to provide a detectable signal, such as withan enzyme, biotin, a radionuclide, fluorophore, chemiluminescer,paramagnetic particle and the like, which are commercially availablefrom many sources, such as Molecular Probes, Inc., Eugene, Oreg., andAmersham Corp., Arlington Heights, Ill., using techniques that are wellknown in the art.

The term “promoter” is used herein for its art-recognized meaning todenote a portion of a gene containing DNA sequences that provide for thebinding of RNA polymerase and initiation of transcription. Promotersequences are commonly, but not always, found in the 5′ non-codingregions of genes.

A “protein” is a macromolecule comprising one or more polypeptidechains. A protein may also comprise non-peptidic components, such ascarbohydrate groups. Carbohydrates and other non-peptidic substituentsmay be added to a protein by the cell in which the protein is produced,and will vary with the type of cell. Proteins are defined herein interms of their amino acid backbone structures; substituents such ascarbohydrate groups are generally not specified, but may be presentnonetheless.

The term “receptor” is used herein to denote a cell-associated protein,or a polypeptide subunit of such a protein, that binds to a bioactivemolecule (the “ligand”) and mediates the effect of the ligand on thecell. Binding of ligand to receptor results in a conformational changein the receptor (and, in some cases, receptor multimerization, i.e.,association of identical or different receptor subunits) that causesinteractions between the effector domain(s) and other molecule(s) in thecell. These interactions in turn lead to alterations in the metabolismof the cell. Metabolic events that are linked to receptor-ligandinteractions include gene transcription, phosphorylation,dephosphorylation, cell proliferation, increases in cyclic AMPproduction, mobilization of cellular calcium, mobilization of membranelipids, cell adhesion, hydrolysis of inositol lipids and hydrolysis ofphospholipids. Cell-surface cytokine receptors are characterized by amulti-domain structure as discussed in more detail below. Thesereceptors are anchored in the cell membrane by a transmembrane domaincharacterized by a sequence of hydrophobic amino acid residues(typically about 21-25 residues), which is commonly flanked bypositively charged residues (Lys or Arg). In general, receptors can bemembrane bound, cytosolic or nuclear; monomeric (e.g., thyroidstimulating hormone receptor, beta-adrenergic receptor) or multimeric(e.g., PDGF receptor, growth hormone receptor, IL-3 receptor, GM-CSFreceptor, G-CSF receptor, erythropoietin receptor and IL-6 receptor).The term “receptor polypeptide” is used to denote complete receptorpolypeptide chains and portions thereof, including isolated functionaldomains (e.g., ligand-binding domains).

A “secretory signal sequence” is a DNA sequence that encodes apolypeptide (a “secretory peptide”) that, as a component of a largerpolypeptide, directs the larger polypeptide through a secretory pathwayof a cell in which it is synthesized. The larger peptide is commonlycleaved to remove the secretory peptide during transit through thesecretory pathway.

A “soluble receptor” is a receptor polypeptide that is not bound to acell membrane. Soluble receptors are most commonly ligand-bindingreceptor polypeptides that lack transmembrane and cytoplasmic domains.Soluble receptors can comprise additional amino acid residues, such asaffinity tags that provide for purification of the polypeptide orprovide sites for attachment of the polypeptide to a substrate, orimmunoglobulin constant region sequences. Many cell-surface receptorshave naturally occurring, soluble counterparts that are produced byproteolysis. Soluble receptor polypeptides are said to be substantiallyfree of transmembrane and intracellular polypeptide segments when theylack sufficient portions of these segments to provide membrane anchoringor signal transduction, respectively.

The term “splice variant” is used herein to denote alternative forms ofRNA transcribed from a gene. Splice variation arises naturally throughuse of alternative splicing sites within a transcribed RNA molecule, orless commonly between separately transcribed RNA molecules, and mayresult in several mRNAs transcribed from the same gene. Splice variantsmay encode polypeptides having altered amino acid sequence. The termsplice variant is also used herein to denote a protein encoded by asplice variant of an mRNA transcribed from a gene.

Molecular weights and lengths of polymers determined by impreciseanalytical methods (e.g., gel electrophoresis) will be understood to beapproximate values. When such a value is expressed as “about” X or“approximately” X, the stated value of X will be understood to beaccurate to ±10%.

All references cited herein are incorporated by reference in theirentirety.

The present invention is based in part upon the discovery of a novel DNAsequence that encodes a protein having the structure of a class Icytokine receptor. The deduced amino acid sequence indicated that theencoded receptor belongs to the receptor subfamily that includes gp130,LIF, IL-12, oncostatin M receptor (OSM-R), WSX-1 receptors (Sprecher CAet al., Biochem. Biophys. Res. Comm. 246:81-90 (1998), DCRS2 (WIPOPublication No. WO00/73451), the IL-2 receptor β-subunit and theβ-common receptor (i.e., IL3, IL-5, and GM-CSF receptor β-subunits. Thepolypeptide has been designated zcytor17. The zcytor17 polynucleotidesequence encodes the entire coding sequence of the predicted protein.Zcytor17 is a novel cytokine receptor that may be involved in immuneregulation, an apoptotic cellular pathway, as a cell-cell signalingmolecule, growth factor receptor, or extracellular matrix associatedprotein with growth factor hormone activity, or the like.

The sequence of the zcytor17 polypeptide was deduced from genomic DNA aswell as identified clones that contained its correspondingpolynucleotide sequence. The clones were obtained from a prostatelibrary. Other libraries that might also be searched for such sequencesinclude PBL, testes, monocytes, thymus, spleen, lymph node, bone marrow,human erythroleukemia, lung (e.g., WI-38 cells) and acute monocyticleukemia cell lines, other lymphoid and hematopoietic cell lines, andthe like.

Nucleotide sequences of representative zcytor17-encoding DNA aredescribed in SEQ ID NO:1 (from nucleotide 171 to 2366), with its deduced732 amino acid sequence described in SEQ ID NO:2; SEQ ID NO:45 (fromnucleotide 162 to 2108), with its deduced 649 amino acid sequencedescribed in SEQ ID NO:46.; and in SEQ ID NO:53 (from nucleotide 497 to2482), with its deduced 662 amino acid sequence described in SEQ IDNO:54. In its entirety, the zcytor17 polypeptide (SEQ ID NO:2, SEQ IDNO:46 or SEQ ID NO:54) represents a full-length polypeptide segment(residue 1 (Met) to residue 732 (Val) of SEQ ID NO:2; residue 1 (Met) toresidue 649 (Ile) of SEQ ID NO:46; residue 1 (Met) to residue 662 (Ile)of SEQ ID NO:54). The domains and structural features of the zcytor17polypeptides are further described below.

Analysis of the zcytor17 polypeptide encoded by the DNA sequence of SEQID NO:1 revealed an open reading frame encoding 732 amino acids (SEQ IDNO:2) comprising a predicted secretory signal peptide of 19 amino acidresidues (residue 1 (Met) to residue 19 (Ala) of SEQ ID NO:2), and amature polypeptide of 713 amino acids (residue 20 (Ala) to residue 732(Val) of SEQ ID NO:2). Analysis of the zcytor17 polypeptide encoded bythe DNA sequence of SEQ ID NO:45 revealed an open reading frame encoding649 amino acids (SEQ ID NO:46) comprising a predicted secretory signalpeptide of 19 amino acid residues (residue 1 (Met) to residue 19 (Ala)of SEQ ID NO:46), and a mature polypeptide of 630 amino acids (residue20 (Ala) to residue 649 (Ile) of SEQ ID NO:46). Analysis of the zcytor17polypeptide encoded by the DNA sequence of SEQ ID NO:53 revealed an openreading frame encoding 662 amino acids (SEQ ID NO:54) comprising apredicted secretory signal peptide of 32 amino acid residues (residue 1(Met) to residue 32 (Ala) of SEQ ID NO:54), and a mature polypeptide of630 amino acids (residue 33 (Ala) to residue 662 (Ile) of SEQ ID NO:54).In addition to the WSXWS motif (SEQ ID NO:3) (corresponding to residues211 to 215 of SEQ ID NO:2 and SEQ ID NO:46; and residues 224 to 228 ofSEQ ID NO:54), the receptor comprises an extracellular domain (residues20 (Ala) to 519 (Glu) of SEQ ID NO:2 and SEQ ID NO:46; residues 33 (Ala)to 532 (Glu) of SEQ ID NO:54) which includes a cytokine-binding domainof approximately 200 amino acid residues (residues 20 (Ala) to 227 (Pro)of SEQ ID NO:2 and SEQ ID NO:46; residues 33 (Ala) to 240 (Pro) of SEQID NO:54); a domain linker (residues 122 (Thr) to 125 (Pro) of SEQ IDNO:2 and SEQ ID NO:46; residues 135 (Thr) to 138 (Pro) of SEQ ID NO:2);a penultimate strand region (residues 194 (Phe) to 202 (Arg) of SEQ IDNO:2 and SEQ ID NO:46; residues 207 (Phe) to 215 (Arg) of SEQ ID NO:54);a fibronectin type III domain (residues 228 (Cys) to 519 (Glu) of SEQ IDNO:2 and SEQ ID NO:46; residues 241 (Cys) to 532 (Glu) of SEQ ID NO:54);a transmembrane domain (residues 520 (Ile) to 543 (Leu) of SEQ ID NO:2and SEQ ID NO:46; residues 533 (Ile) to 556 (Leu) of SEQ ID NO:54);complete intracellular signaling domain (residues 544 (Lys) to 732 (Val)of SEQ ID NO:2; residues 544 (Lys) to 649 (Ile) of SEQ ID NO:46; andresidues 557 (Lys) to 662 (Ile) of SEQ ID NO:54) which contains a “BoxI” signaling site (residues 554 (Trp) to 560 (Pro) of SEQ ID NO:2 andSEQ ID NO:46; residues 567 (Trp) to 573 (Pro) of SEQ ID NO:54), and a“Box II” signaling site (residues 617 (Gln) to 620 (Phe) of SEQ ID NO:2and SEQ ID NO:46; residues 630 (Gln) to 633 (Phe) of SEQ ID NO:54).Those skilled in the art will recognize that these domain boundaries areapproximate, and are based on alignments with known proteins andpredictions of protein folding. In addition to these domains, conservedreceptor features in the encoded receptor include (as shown in SEQ IDNO:2 and SEQ ID NO:46) a conserved Cys residue at position 30 (position43 as shown in SEQ ID NO:54), CXW motif (wherein X is any amino acid) atpositions 40-42 (positions 53-55 as shown in SEQ ID NO:54), Trp residueat position 170 (position 183 as shown in SEQ ID NO:54), and a conservedArg residue at position 202 (position 215 as shown in SEQ ID NO:54). Thecorresponding polynucleotides encoding the zcytor17 polypeptide regions,domains, motifs, residues and sequences described above are as shown inSEQ ID NO:1, SEQ ID NO:45, and SEQ ID NO:53.

Moreover, truncated forms of the zcytor17 polypeptide appear to benaturally expressed. Both forms encode soluble zcytor17 receptors. Apolynucleotide encoding a “long-form” of the soluble zcytor17 receptor,truncated within the fibronectin type III domain, is shown in SEQ IDNO:17 and the corresponding polypeptide is shown in SEQ ID NO:18. Thistruncated form encodes residues 1 (Met) through 324 (Lys) of SEQ ID NO:2and SEQ ID NO:46), and thus comprises an intact signal sequence, WSXWS(SEQ ID NO:3) motif, linker, cytokine binding domain, penultimatestrand, and conserved, Cys, CXW motif, Trp and Arg residues as describedabove. A polynucleotide encoding a “short-form” of the soluble zcytor17receptor, truncated at the end of the cytokine binding domain is shownin SEQ ID NO:21 and the corresponding polypeptide is shown in SEQ IDNO:22. This truncated form encodes a 239 residue polypeptide that isidentical to residues 1 (Met) through 225 (Glu) of SEQ ID NO:2 and SEQID NO:46 and then diverges, and thus comprises an intact signalsequence, WSXWS (SEQ ID NO:3) motif, linker, cytokine binding domain,penultimate strand, and conserved, Cys, CXW motif, Trp and Arg residuesas described above. A multiple alignment of the truncated forms comparedto the full-length forms of zcytor17 is shown in FIG. 1.

Moreover, the zcytor17 cDNA of SEQ ID NO:1, SEQ ID NO:45, SEQ ID NO:17,and SEQ ID NO:21 encode polypeptides that may use an alternativeinitiating methionine (at nucleotide 75 of SEQ ID NO:1, at nucleotide 66of SEQ ID NO:45, at nucleotide 66 of SEQ ID NO:17, and at nucleotide 66of SEQ ID NO:21) that would encode a polypeptide in the same openreading frame (ORF) as the zcytor17 polypeptides of SEQ ID NO:2, SEQ IDNO:46, SEQ ID NO:18, and SEQ ID NO:22. Use of the alternative initiatingmethionine would add 32 amino acids (shown in SEQ ID NO:48) in-frame tothe N-terminus of SEQ ID NO:2, SEQ ID NO:46, SEQ ID NO:18, and SEQ IDNO:2. In addition, nucleotide 536 of SEQ ID NO:53 may serve as analternative initiating methionine, thus generating the same N-terminus(starting at amino acid 14 (Met) of SEQ ID NO:54) and signal polypeptidesequence, as SEQ. ID NO:2, SEQ ID NO:46, SEQ ID NO:18, and SEQ ID NO:22.Moreover, the second Met at amino acid number 2 in the SEQ ID NO:2, SEQID NO:46, SEQ ID NO:18, and SEQ ID NO:22 sequences (similarly at aminoacid number 15 (Met) in SEQ ID NO:54) may also serve as an alternativestarting methionine for the polypeptides.

The presence of transmembrane regions, and conserved and low variancemotifs generally correlates with or defines important structural regionsin proteins. Regions of low variance (e.g., hydrophobic clusters) aregenerally present in regions of structural importance (Sheppard, P. etal., supra.). Such regions of low variance often contain rare orinfrequent amino acids, such as Tryptophan. The regions flanking andbetween such conserved and low variance motifs may be more variable, butare often functionally significant because they may relate to or defineimportant structures and activities such as binding domains, biologicaland enzymatic activity, signal transduction, cell-cell interaction,tissue localization domains and the like.

The regions of conserved amino acid residues in zcytor17, describedabove, can be used as tools to identify new family members. Forinstance, reverse transcription-polymerase chain reaction (RT-PCR) canbe used to amplify sequences encoding the conserved regions from RNAobtained from a variety of tissue sources or cell lines. In particular,highly degenerate primers designed from the zcytor17 sequences areuseful for this purpose. Designing and using such degenerate primers maybe readily performed by one of skill in the art.

The present invention provides polynucleotide molecules, including DNAand RNA molecules that encode the zcytor17 polypeptides disclosedherein. Those skilled in the art will recognize that, in view of thedegeneracy of the genetic code, considerable sequence variation ispossible among these polynucleotide molecules. SEQ ID NO:4, SEQ ID NO:47and SEQ ID NO:55 are degenerate DNA sequences that encompass all DNAsthat encode the zcytor17 polypeptide of SEQ ID NO:2, SEQ ID NO:46 andSEQ ID NO:54 respectively. Those skilled in the art will recognize thatthe degenerate sequences of SEQ ID NO:4, SEQ ID NO:47 and SEQ ID NO:55also provide all RNA sequences encoding SEQ ID NO:2, SEQ ID NO:46 andSEQ ID NO:54 by substituting U for T. Thus, zcytor17polypeptide-encoding polynucleotides comprising nucleotide 1 tonucleotide 2196 of SEQ ID NO:4, nucleotide 1 to nucleotide 1947 of SEQID NO:47, and nucleotide 1 to nucleotide 1986 of SEQ ID NO:55 and theirRNA equivalents are contemplated by the present invention. Table 1 setsforth the one-letter codes used within SEQ ID NO:4, SEQ ID NO:47 and SEQID NO:55 to denote degenerate nucleotide positions. “Resolutions” arethe nucleotides denoted by a code letter. “Complement” indicates thecode for the complementary nucleotide(s). For example, the code Ydenotes either C or T, and its complement R denotes A or G, A beingcomplementary to T, and G being complementary to C. TABLE 1 NucleotideResolution Complement Resolution A A T T C C G G G G C C T T A A R A|G YC|T Y C|T R A|G M A|C K G|T K G|T M A|C S C|G S C|G W A|T W A|T H A|C|TD A|G|T B C|G|T V A|C|G V A|C|G B C|G|T D A|G|T H A|C|T N A|C|G|T NA|C|G|T

The degenerate codons used in SEQ ID NO:4, SEQ ID NO:47 and SEQ IDNO:55, encompassing all possible codons for a given amino acid, are setforth in Table 2. TABLE 2 One Amino Letter Degenerate Acid Code CodonsCodon Cys C TGC TGT TGY Ser S AGC AGT TCA TCC TCG TCT WSN Thr T ACA ACCACG ACT ACN Pro P CCA CCC CCG CCT CCN Ala A GCA GCC GCG GCT GCN Gly GGGA GGC GGG GGT GGN Asn N AAC AAT AAY Asp D GAC GAT GAY Glu E GAA GAGGAR Gln Q CAA CAG CAR His H CAC CAT CAY Arg R AGA AGG CGA CGC CGG CGTMGN Lys K AAA AAG AAR Met M ATG ATG Ile I ATA ATC ATT ATH Leu L CTA CTCCTG CTT TTA TTG YTN Val V GTA GTC GTG GTT GTN Phe F TTC TTT TTY Tyr YTAC TAT TAY Trp W TGG TGG Ter . TAA TAG TGA TRR Asn|Asp B RAY Glu|Gln ZSAR Any X NNN

One of ordinary skill in the art will appreciate that some ambiguity isintroduced in determining a degenerate codon, representative of allpossible codons encoding each amino acid. For example, the degeneratecodon for serine (WSN) can, in some circumstances, encode arginine(AGR), and the degenerate codon for arginine (MGN) can, in somecircumstances, encode serine (AGY). A similar relationship existsbetween codons encoding phenylalanine and leucine. Thus, somepolynucleotides encompassed by the degenerate sequence may encodevariant amino acid sequences, but one of ordinary skill in the art caneasily identify such variant sequences by reference to the amino acidsequences of SEQ ID NO:2, SEQ ID NO:46 and SEQ ID NO:54; or SEQ ID NO:57and SEQ ID NO:93. Variant sequences can be readily tested forfunctionality as described herein.

One of ordinary skill in the art will also appreciate that differentspecies can exhibit “preferential codon usage.” In general, see,Grantham, et al., Nuc. Acids Res. 8:1893-912, 1980; Haas, et al. Curr.Biol. 6:315-24, 1996; Wain-Hobson, et al., Gene 13:355-64, 1981;Grosjean and Fiers, Gene 18:199-209, 1982; Holm, Nuc. Acids Res.14:3075-87, 1986; Ikemura, J. Mol. Biol. 158:573-97, 1982. As usedherein, the term “preferential codon usage” or “preferential codons” isa term of art referring to protein translation codons that are mostfrequently used in cells of a certain species, thus favoring one or afew representatives of the possible codons encoding each amino acid (SeeTable 2). For example, the amino acid Threonine (Thr) may be encoded byACA, ACC, ACG, or ACT, but in mammalian cells ACC is the most commonlyused codon; in other species, for example, insect cells, yeast, virusesor bacteria, different Thr codons may be preferential. Preferentialcodons for a particular species can be introduced into thepolynucleotides of the present invention by a variety of methods knownin the art. Introduction of preferential codon sequences intorecombinant DNA can, for example, enhance production of the protein bymaking protein translation more efficient within a particular cell typeor species. Therefore, the degenerate codon sequences disclosed in SEQID NO:4, SEQ ID NO:47 and SEQ ID NO:55 serve as templates for optimizingexpression of zcytor17 polynucleotides in various cell types and speciescommonly used in the art and disclosed herein. Sequences containingpreferential codons can be tested and optimized for expression invarious species, and tested for functionality as disclosed herein.

Within preferred embodiments of the invention the isolatedpolynucleotides will hybridize to similar sized regions of SEQ ID NO:1,SEQ ID NO:45, or SEQ ID NO:54; or SEQ ID NO:57 and SEQ ID NO:93; or asequence complementary thereto, under stringent conditions. In general,stringent conditions are selected to be about 5° C. lower than thethermal melting point (T_(M)) for the specific sequence at a definedionic strength and pH. The T_(M) is the temperature (under defined ionicstrength and pH) at which 50% of the target sequence hybridizes to aperfectly matched probe. Numerous equations for calculating T_(m) areknown in the art, and are specific for DNA, RNA and DNA-RNA hybrids andpolynucleotide probe sequences of varying length (see, for example,Sambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition(Cold Spring Harbor Press 1989); Ausubel et al., (eds.), CurrentProtocols in Molecular Biology (John Wiley and Sons, Inc. 1987); Bergerand Kimmel (eds.), Guide to Molecular Cloning Techniques, (AcademicPress, Inc. 1987); and Wetmur, Crit. Rev. Biochem. Mol. Biol. 26:227(1990)). Sequence analysis software such as OLIGO 6.0 (LSR; Long Lake,Minn.) and Primer Premier 4.0 (Premier Biosoft International; Palo Alto,Calif.), as well as sites on the Internet, are available tools foranalyzing a given sequence and calculating T_(m) based on user definedcriteria. Such programs can also analyze a given sequence under definedconditions and identify suitable probe sequences. Typically,hybridization of longer polynucleotide sequences (e.g., >50 base pairs)is performed at temperatures of about 20-25° C. below the calculatedT_(m). For smaller probes (e.g., <50 base pairs) hybridization istypically carried out at the T_(m) or 5-10° C. below. This allows forthe maximum rate of hybridization for DNA-DNA and DNA-RNA hybrids.Higher degrees of stringency at lower temperatures can be achieved withthe addition of formamide which reduces the T_(m) of the hybrid about 1°C. for each 1% formamide in the buffer solution. Suitable stringenthybridization conditions are equivalent to about a 5 h to overnightincubation at about 42° C. in a solution comprising: about 40-50%formamide, up to about 6×SSC, about 5× Denhardt's solution, zero up toabout 10% dextran sulfate, and about 10-20 μg/ml denaturedcommercially-available carrier DNA. Generally, such stringent conditionsinclude temperatures of 20-70° C. and a hybridization buffer containingup to 6×SSC and 0-50% formamide; hybridization is then followed bywashing filters in up to about 2×SSC. For example, a suitable washstringency is equivalent to 0.1×SSC to 2×SSC, 0.1% SDS, at 55° C. to 65°C. Different degrees of stringency can be used during hybridization andwashing to achieve maximum specific binding to the target sequence.Typically, the washes following hybridization are performed atincreasing degrees of stringency to remove non-hybridized polynucleotideprobes from hybridized complexes. Stringent hybridization and washconditions depend on the length of the probe, reflected in the Tm,hybridization and wash solutions used, and are routinely determinedempirically by one of skill in the art.

As previously noted, the isolated polynucleotides of the presentinvention include DNA and RNA. Methods for preparing DNA and RNA arewell known in the art. In general, RNA is isolated from a tissue or cellthat produces. large amounts of zcytor17 RNA. Such tissues and cells areidentified by Northern blotting (Thomas, Proc. Natl. Acad. Sci. USA77:5201, 1980), and include PBLs, spleen, thymus, bone marrow, prostate,and lymph tissues, human erythroleukemia cell lines, acute monocyticleukemia cell lines, other lymphoid and hematopoietic cell lines, andthe like. Total RNA can be prepared using guanidinium isothiocyanateextraction followed by isolation by centrifugation in a CsCl gradient(Chirgwin et al., Biochemistry 18:52-94, 1979). Poly (A)⁺ RNA isprepared from total RNA using the method of Aviv and Leder (Proc. Natl.Acad. Sci. USA 69:1408-12, 1972). Complementary DNA (cDNA) is preparedfrom poly(A)⁺ RNA using known methods. In the alternative, genomic DNAcan be isolated. Polynucleotides encoding zcytor17 polypeptides are thenidentified and isolated by, for example, hybridization or polymerasechain reaction (PCR) (Mullis, U.S. Pat. No. 4,683,202).

A full-length clone encoding zcytor17 can be obtained by conventionalcloning procedures. Complementary DNA (cDNA) clones are preferred,although for some applications (e.g., expression in transgenic animals)it may be preferable to use a genomic clone, or to modify a cDNA cloneto include at least one genomic intron. Methods for preparing cDNA andgenornic clones are well known and within the level of ordinary skill inthe art, and include the use of the sequence disclosed herein, or partsthereof, for probing or priming a library. Expression libraries can beprobed with antibodies to zcytor17, receptor fragments, or otherspecific binding partners.

The polynucleotides of the present invention can also be synthesizedusing DNA synthesis machines. Currently the method of choice is thephosphoramidite method. If chemically synthesized double stranded DNA isrequired for an application such as the synthesis of a gene or a genefragment, then each complementary strand is made separately. Theproduction of short polynucleotides (60 to 80 bp) is technicallystraightforward and can be accomplished by synthesizing thecomplementary strands and then annealing them. However, for producinglonger polynucleotides (>300 bp), special strategies are usuallyemployed, because the coupling efficiency of each cycle during chemicalDNA synthesis is seldom 100%. To overcome this problem, synthetic genes(double-stranded) are assembled in modular form from single-strandedfragments that are from 20 to 100 nucleotides in length.

An alternative way to prepare a full-length gene is to synthesize aspecified set of overlapping oligonucleotides (40 to 100 nucleotides).After the 3′ and 5′ short overlapping complementary regions (6 to 10nucleotides) are annealed, large gaps still remain, but the shortbase-paired regions are both long enough and stable enough to hold thestructure together. The gaps are filled and the DNA duplex is completedvia enzymatic DNA synthesis by E. coli DNA polymerase I. After theenzymatic synthesis is completed, the nicks are sealed with T4 DNAligase. Double-stranded constructs are sequentially linked to oneanother to form the entire gene sequence which is verified by DNAsequence analysis. See Glick and Pasternak, Molecular Biotechnology,Principles & Applications of Recombinant DNA, (ASM Press, Washington,D.C. 1994); Itakura et al., Annu. Rev. Biochem. 53: 323-56, 1984 andClimie et al., Proc. Natl. Acad. Sci. USA 87:633-7, 1990. Moreover,other sequences are generally added that contain signals for properinitiation and termination of transcription and translation.

The present invention further provides counterpart polypeptides andpolynucleotides from other species (orthologs). These species include,but are not limited to mammalian, avian, amphibian, reptile, fish,insect and other vertebrate and invertebrate species. Of particularinterest are zcytor17 polypeptides from other mammalian species,including murine, porcine, ovine, bovine, canine, feline, equine, andother primate polypeptides. Orthologs of human zcytor17 can be clonedusing information and compositions provided by the present invention incombination with conventional cloning techniques. For example, a cDNAcan be cloned using mRNA obtained from a tissue or cell type thatexpresses zcytor17 as disclosed herein. Suitable sources of mRNA can beidentified by probing Northern blots with probes designed from thesequences disclosed herein. A library is then prepared from mRNA of apositive tissue or cell line. A zcytor17-encoding cDNA can then beisolated by a variety of methods, such as by probing with a complete orpartial human cDNA or with one or more sets of degenerate probes basedon the disclosed sequences. A cDNA can also be cloned using PCR (Mullis,supra.), using primers designed from the representative human zcytor17sequence disclosed herein. Within an additional method, the cDNA librarycan be used to transform or transfect host cells, and expression of thecDNA of interest can be detected with an antibody to zcytor17polypeptide. Similar techniques can also be applied to the isolation ofgenomic clones.

A polynucleotide sequence for the mouse ortholog of human zcytor17 hasbeen identified and is shown in SEQ ID NO:56 and the corresponding aminoacid sequence shown in SEQ ID NO:57. Analysis of the mouse zcytor17polypeptide encoded by the DNA sequence of SEQ ID NO:56 revealed an openreading frame encoding 662 amino acids (SEQ ID NO:57) comprising apredicted secretory signal peptide of 45 amino acid residues (residue 1(Met) to residue 45 (Ala) of SEQ ID NO:57), and a mature polypeptide of617 amino acids (residue46 (Val) to residue 662 (Cys) of SEQ ID NO:57).Moreover, an additional Met residue, Met (28) can be used as a startingmethionine; comprising a second predicted secretory signal peptide of 18amino acid residues (residue 28 (Met) to residue 45 (Ala) of SEQ IDNO:57), and the same mature polypeptide of 617 amino acids (residue46(Val) to residue 662 (Cys) of SEQ ID NO:57. In addition to the WSXWSmotif (SEQ ID NO:3) corresponding to residues 224-228 of SEQ ID NO:57,the receptor comprises an extracellular domain from residues 46 (Val) to533 (Glu) of SEQ ID NO:57) that includes a cytokine-binding domain ofapproximately 200 amino acid residues (residues 46 (Val) to 240 (Pro) ofSEQ ID NO:57) and a fibronectin III domain (residues 241 (His) to 533(Glu) of SEQ ID NO:57); a CXW motif (residues 66 (Cys) to 68 (Trp) ofSEQ ID NO:57); a domain linker (residues 142 (Thr) to 145 (Pro) of SEQID NO:57); a penultimate strand region (residues 207 (Phe) to 215 (Arg)of SEQ ID NO:57); a transmembrane domain (residues 534 (Ile) to 550(Ile) of SEQ ID NO:57); complete intracellular signaling domain(residues 551 (Lys) to 662 (Cys) of SEQ ID NO:57) which contains a “BoxI” signaling site (residues 568 (Cys) to 574 (Pro) of SEQ ID NO:57), anda “Box II” signaling site (residues 628 (Glu) to 631 (leu) of SEQ IDNO:57). Conserved residues common to class I cytokine receptors, are atresidues 56 (Cys), 187 (Trp), and 215 (Arg). A comparison of the humanand mouse amino acid sequences reveals that both the human andorthologous polypeptides contain corresponding structural featuresdescribed above (and, see, FIG. 2). The mature sequence for the mousezcytor17 begins at Val₄₆ (as shown in SEQ ID NO:57), which correspondsto Ala₃₃ (as shown in SEQ ID NO:54) in the human sequence. There isabout 61% identity between the mouse and human sequences over the entireamino acid sequence corresponding to SEQ ID NO:54 and SEQ ID NO:57. Theabove percent identity was determined using a FASTA program with ktup=1,gap opening penalty=12, gap extension penalty=2, and substitutionmatrix=BLOSUM62, with other parameters set as default. The correspondingpolynucleotides encoding the mouse zcytor17 polypeptide regions,domains, motifs, residues and sequences described above are as shown inSEQ ID NO:56.

Moreover, a truncated soluble form of the mouse zcytor17 receptorpolypeptide appears to be naturally expressed. A polynucleotide sequencefor a truncated soluble form of the mouse zcytor17 receptor has beenidentified and is shown in SEQ ID NO:92 and the corresponding amino acidsequence shown in SEQ ID NO:93. Analysis of the truncated soluble mousezcytor17 polypeptide encoded by the DNA sequence of SEQ ID NO:92revealed an open reading frame encoding 547 amino acids (SEQ ID NO:93)comprising a predicted secretory signal peptide of 45 amino acidresidues (residue 1 (Met) to residue 45 (Ala) of SEQ ID NO:93), and amature polypeptide of 502 amino acids (residue46 (Val) to residue 547(Val) of SEQ ID NO:93). Moreover, an additional Met residue, Met (28)can be used as a starting methionine; comprising a second predictedsecretory signal peptide of 18 amino acid residues (residue 28 (Met) toresidue 45 (Ala) of SEQ ID NO:93), and the same mature polypeptide of502 amino acids (residue46 (Val) to residue 547 (Val) of SEQ ID NO:93.In addition to the WSXWS motif (SEQ ID NO:3) corresponding to residues224-228 of SEQ ID NO:93, the receptor comprises an extracellular domainfrom residues 46 (Val) to 533 (Trp) of SEQ ID NO:93) that includes acytokine-binding domain of approximately 200 amino acid residues(residues 46 (Val) to 240 (Pro) of SEQ ID NO:93) and a fibronectin IIIdomain (residues 241 (His) to 533 (Trp) of SEQ ID NO:93); a CXW motif(residues 66 (Cys) to 68 (Trp) of SEQ ID NO:93); a domain linker(residues 142 (Thr) to 145 (Pro) of SEQ ID NO:93); a penultimate strandregion (residues 207 (Phe) to 215 (Arg) of SEQ ID NO:93); and aC-terminal tail region (residues 534 (Leu) to 547 (Val). Conservedresidues common to class I cytokine receptors, are at residues 56 (Cys),187 (Trp), and 215 (Arg). A comparison of the human and mouse amino acidsequences, including the truncated soluble mouse zcytor17, reveals thatboth the human and orthologous polypeptides contain correspondingstructural features described above (and, see, FIG. 2). Thecorresponding polynucleotides encoding the truncated soluble mousezcytor17 polypeptide regions, domains, motifs, residues and sequencesdescribed above are as shown in SEQ ID NO:92.

Cytokine receptor subunits are characterized by a multi-domain structurecomprising an extracellular domain, a transmembrane domain that anchorsthe polypeptide in the cell membrane, and an intracellular domain. Theextracellular domain may be a ligand-binding domain, and theintracellular domain may be an effector domain involved in signaltransduction, although ligand-binding and effector functions may resideon separate subunits of a multimeric receptor. The ligand-binding domainmay itself be a multi-domain structure. Multimeric receptors includehomodimers (e.g., PDGF receptor αα and ββ isoforms, erythropoietinreceptor, MPL, and G-CSF receptor), heterodimers whose subunits eachhave ligand-binding and effector domains (e.g., PDGF receptor αβisoform), and multimers having component subunits with disparatefunctions (e.g., IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, and GM-CSFreceptors). Some receptor subunits are common to a plurality ofreceptors. For example, the AIC2B subunit, which cannot bind ligand onits own but includes an intracellular signal transduction domain, is acomponent of IL-3 and GM-CSF receptors. Many cytokine receptors can beplaced into one of four related families on the basis of the structureand function. Hematopoietic receptors, for example, are characterized bythe presence of a domain containing conserved cysteine residues and theWSXWS motif (SEQ ID NO:3). Cytokine receptor structure has been reviewedby Urdal, Ann. Reports Med. Chem. 26:221-228, 1991 and Cosman, Cytokine5:95-106, 1993. Under selective pressure for organisms to acquire newbiological functions, new receptor family members likely arise fromduplication of existing receptor genes leading to the existence ofmulti-gene families. Family members thus contain vestiges of theancestral gene, and these characteristic features can be exploited inthe isolation and identification of additional family members. Thus, thecytokine receptor superfamily is subdivided into several families, forexample, the immunoglobulin family (including CSF-1, MGF, IL-1, and PDGFreceptors); the hematopoietin family (including IL-2 receptor β-subunit,GM-CSF receptor α-subunit, GM-CSF receptor β-subunit; and G-CSF, EPO,IL-3, IL-4, IL-5, IL-6, IL-7, and IL-9 receptors); TNF receptor family(including TNF (p80) TNF (p60) receptors, CD27, CD30, CD40, Fas, and NGFreceptor).

Analysis of the zcytor17 sequence suggests that it is a member of thesame receptor subfamily as the gp130, LIF, IL-12, WSX-1, IL-2 receptorβ-subunit, IL-3, IL-4, and IL-6 receptors. Certain receptors in thissubfamily (e.g., G-CSF) associate to form homodimers that transduce asignal. Other members of the subfamily (e.g., gp130, IL-6, IL-11, andLIF receptors) combine with a second subunit (termed a β-subunit) tobind ligand and transduce a signal. Specific β-subunits associate with aplurality of specific cytokine receptor subunits. For example, theβ-subunit gp130 (Hibi et al., Cell 63:1149-1157, 1990) associates withreceptor subunits specific for IL-6, IL-11, and LIF (Gearing et al.,EMBO J. 10:2839-2848, 1991; Gearing et al., U.S. Pat. No. 5,284,755).Oncostatin M binds to a heterodimer of LIF receptor and gp130. CNTFbinds to trimeric receptors comprising CNTF receptor, LIF receptor, andgp130 subunits.

Those skilled in the art will recognize that the sequences disclosed inSEQ ID NO:1, SEQ ID NO:45 and SEQ ID NO:53 represent alleles of humanzcytor17 and that allelic variation and alternative splicing areexpected to occur. Allelic variants of this sequence can be cloned byprobing cDNA or genomic libraries from different individuals accordingto standard procedures. Allelic variants of the DNA sequence shown inSEQ ID NO:1, SEQ ID NO:45 or SEQ ID NO:53, including those containingsilent mutations and those in which mutations result in amino acidsequence changes, are within the scope of the present invention, as areproteins which are allelic variants of SEQ ID NO:2, SEQ ID NO:46, SEQ IDNO:54 SEQ ID NO:57 or SEQ ID NO:93. cDNAs generated from alternativelyspliced mRNAs, which retain the properties of the zcytor17 polypeptideare included within the scope of the present invention, as arepolypeptides encoded by such cDNAs and mRNAs. Allelic variants andsplice variants of these sequences can be cloned by probing cDNA orgenomic libraries from different individuals or tissues according tostandard procedures known in the art. For example, the short-form andlong-form soluble zcytor17 receptors described above, and in SEQ IDNO:17 and SEQ ID NO:18 or SEQ ID NO:21 and SEQ ID NO:22 can beconsidered allelic or splice variants of zcytor17.

The present invention also provides isolated zcytor17 polypeptides thatare substantially similar to the polypeptides of SEQ ID NO:2, SEQ IDNO:46 or SEQ ID NO:54 and their orthologs, e.g., SEQ ID NO:57 and SEQ IDNO:93. The term “substantially similar” is used herein to denotepolypeptides having at least 70%, more preferably at least 80%, sequenceidentity to the sequences shown in SEQ ID NO:2, SEQ ID NO:46 or SEQ IDNO:54 or their orthologs, e.g., SEQ ID NO:57 and SEQ ID NO:93. Suchpolypeptides will more preferably be at least 90% identical, and mostpreferably 95% or more identical to SEQ ID NO:2, SEQ ID NO:46 and SEQ IDNO:54 or its orthologs.) Percent sequence identity is determined byconventional methods. See, for example, Altschul et al., Bull. Math.Bio. 48: 603-616, 1986 and Henikoff and Henikoff, Proc. Natl. Acad. Sci.USA 89:10915-10919, 1992. Briefly, two amino acid sequences are alignedto optimize the alignment scores using a gap opening penalty of 10, agap extension penalty of 1, and the “blosum 62” scoring matrix ofHenikoff and Henikoff (ibid.) as shown in Table 3 (amino acids areindicated by the standard one-letter codes). The percent identity isthen calculated as:$\frac{{Total}\quad{number}\quad{of}\quad{identical}\quad{matches}}{\begin{bmatrix}{{length}\quad{of}\quad{the}\quad{longer}\quad{sequence}\quad{plus}\quad{the}} \\{{number}\quad{of}\quad{gaps}\quad{introduced}\quad{into}\quad{the}\quad{longer}} \\{{sequence}\quad{in}\quad{order}\quad{to}\quad{align}\quad{the}\quad{two}\quad{sequences}}\end{bmatrix}} \times 100$ TABLE 3 A R N D C Q E G H I L K M F P S T W YV A 4 R −1 5 N −2 0 6 D −2 −2 1 6 C 0 −3 −3 −3 9 Q −1 1 0 0 −3 5 E −1 00 2 −4 2 5 G 0 −2 0 −1 −3 −2 −2 6 H −2 0 1 −1 −3 0 0 −2 8 I −1 −3 −3 −3−1 −3 −3 −4 −3 4 L −1 −2 −3 −4 −1 −2 −3 −4 −3 2 4 K −1 2 0 −1 −3 1 1 −2−1 −3 −2 5 M −1 −1 −2 −3 −1 0 −2 −3 −2 1 2 −1 5 F −2 −3 −3 −3 −2 −3 −3−3 −1 0 0 −3 0 6 P −1 −2 −2 −1 −3 −1 −1 −2 −2 −3 −3 −1 −2 −4 7 S 1 −1 10 −1 0 0 0 −1 −2 −2 0 −1 −2 −1 4 T 0 −1 0 −1 −1 −1 −1 −2 −2 −1 −1 −1 −1−2 −1 1 5 W −3 −3 −4 −4 −2 −2 −3 −2 −2 −3 −2 −3 −1 1 −4 −3 −2 11 Y −2 −2−2 −3 −2 −1 −2 −3 2 −1 −1 −2 −1 3 −3 −2 −2 2 7 V 0 −3 −3 −3 −1 −2 −2 −3−3 3 1 −2 1 −1 −2 −2 0 −3 −1 4

Sequence identity of polynucleotide molecules is determined by similarmethods using a ratio as disclosed above.

Those skilled in the art appreciate that there are many establishedalgorithms available to align two amino acid sequences. The “FASTA”similarity search algorithm of Pearson and Lipman is a suitable proteinalignment method for examining the level of identity shared by an aminoacid sequence disclosed herein and the amino acid sequence of a putativevariant zcytor17. The FASTA algorithm is described by Pearson andLipman, Proc. Nat'l. Acad. Sci. USA 85:2444 (1988), and by Pearson,Meth. Enzymol. 183:63 (1990).

Briefly, FASTA first characterizes sequence similarity by identifyingregions shared by the query sequence (e.g., SEQ ID NO:2, SEQ ID NO:46,SEQ ID NO:54, SEQ ID NO:57 and SEQ ID NO:93) and a test sequence thathave either the highest density of identities (if the ktup variableis 1) or pairs of identities (if ktup=2), without consideringconservative amino acid substitutions, insertions, or deletions. The tenregions with the highest density of identities are then rescored bycomparing the similarity of all paired amino acids using an amino acidsubstitution matrix, and the ends of the regions are “trimmed” toinclude only those residues that contribute to the highest score. Ifthere are several regions with scores greater than the “cutoff” value(calculated by a predetermined formula based upon the length of thesequence and the ktup value), then the trimmed initial regions areexamined to determine whether the regions can be joined to form anapproximate alignment with gaps. Finally, the highest scoring regions ofthe two amino acid sequences are aligned using a modification of theNeedleman-Wunsch-Sellers algorithm (Needleman and Wunsch, J. Mol. Biol.48:444 (1970); Sellers, SIAM J. Appl. Math. 26:787 (1974)), which allowsfor amino acid insertions and deletions. Preferred parameters for FASTAanalysis are: ktup=1, gap opening penalty=10, gap extension penalty=1,and substitution matrix=BLOSUM62, with other parameters set as default.These parameters can be introduced into a FASTA program by modifying thescoring matrix file (“SMATRIX”), as explained in Appendix 2 of Pearson,Meth. Enzymol. 183:63 (1990).

FASTA can also be used to determine the sequence identity of nucleicacid molecules using a ratio as disclosed above. For nucleotide sequencecomparisons, the ktup value can range between one to six, preferablyfrom three to six, most preferably three, with other FASTA programparameters set as default.

The BLOSUM62 table (Table 3) is an amino acid substitution matrixderived from about 2,000 local multiple alignments of protein sequencesegments, representing highly conserved regions of more than 500 groupsof related proteins (Henikoff and Henikoff, Proc. Nat'l. Acad. Sci. USA89:10915 (1992)). Accordingly, the BLOSUM62 substitution frequencies canbe used to define conservative amino acid substitutions that may beintroduced into the amino acid sequences of the present invention.Although it is possible to design amino acid substitutions based solelyupon chemical properties (as discussed below), the language“conservative amino acid substitution” preferably refers to asubstitution represented by a BLOSUM62 value of greater than −1. Forexample, an amino acid substitution is conservative if the substitutionis characterized by a BLOSUM62 value of 0, 1, 2, or 3. According to thissystem, preferred conservative amino acid substitutions arecharacterized by a BLOSUM62 value of at least 1 (e.g., 1, 2 or 3), whilemore preferred conservative amino acid substitutions are characterizedby a BLOSUM62 value of at least 2 (e.g., 2 or 3).

Variant zcytor17 polypeptides or substantially homologous zcytor17polypeptides are characterized as having one or more amino acidsubstitutions, deletions or additions. These changes are preferably of aminor nature, that is conservative amino acid substitutions (see Table4) and other substitutions that do not significantly affect the foldingor activity of the polypeptide; small deletions, typically of one toabout 30 amino acids; and small amino- or carboxyl-terminal extensions,such as an amino-terminal methionine residue, a small linker peptide ofup to about 20-25 residues, or an affinity tag. The present inventionthus includes polypeptides that comprise a sequence that is at least80%, preferably at least 90%, and more preferably 95% or more identicalto the corresponding region of SEQ ID NO:2, SEQ ID NO:46, SEQ ID NO:54,SEQ ID NO:57 or SEQ ID NO:93excluding the tags, extension, linkersequences and the like. Polypeptides comprising affinity tags canfurther comprise a proteolytic cleavage site between the zcytor17polypeptide and the affinity tag. Suitable sites include thrombincleavage sites and factor Xa cleavage sites. TABLE 4 Conservative aminoacid substitutions Basic: arginine lysine histidine Acidic: glutamicacid aspartic acid Polar: glutamine asparagine Hydrophobic: leucineisoleucine valine Aromatic: phenylalanine tryptophan tyrosine Small:glycine alanine serine threonine methionine

The present invention further provides a variety of other polypeptidefusions and related multimeric proteins comprising one or morepolypeptide fusions. For example, a zcytor17 polypeptide can be preparedas a fusion to a dimerizing protein as disclosed in U.S. Pat. Nos.5,155,027 and 5,567,584. Preferred dimerizing proteins in this regardinclude immunoglobulin constant region domains. Immunoglobulin-zcytor17polypeptide fusions can be expressed in genetically engineered cells toproduce a variety of multimeric zcytor17 analogs. Auxiliary domains canbe fused to zcytor17 polypeptides to target them to specific cells,tissues, or macromolecules (e.g., collagen). A zcytor17 polypeptide canbe fused to two or more moieties, such as an affinity tag forpurification and a targeting domain. Polypeptide fusions can alsocomprise one or more cleavage sites, particularly between domains. See,Tuan et al., Connective Tissue Research 34:1-9, 1996.

The proteins of the present invention can also comprise non-naturallyoccurring amino acid residues. Non-naturally occurring amino acidsinclude, without limitation, trans-3-methylproline, 2,4-methanoproline,cis-4-hydroxyproline, trans-4-hydroxyproline, N-methylglycine,allo-threonine, methylthreonine, hydroxyethylcysteine,hydroxyethylhomocysteine, nitroglutamine, homoglutamine, pipecolic acid,thiazolidine carboxylic acid, dehydroproline, 3- and 4-methylproline,3,3-dimethylproline, tert-leucine, norvaline, 2-azaphenylalanine,3-azaphenylalanine, 4-azaphenylalanine, and 4-fluorophenylalanine.Several methods are known in the art for incorporating non naturallyoccurring amino acid residues into proteins. For example, an in vitrosystem can be employed wherein nonsense mutations are suppressed usingchemically aminoacylated suppressor tRNAs. Methods for synthesizingamino acids and aminoacylating tRNA are known in the art. Transcriptionand translation of plasmids containing nonsense mutations is carried outin a cell-free system comprising an E. coli S30 extract and commerciallyavailable enzymes and other reagents. Proteins are purified bychromatography. See, for example, Robertson et al., J. Am. Chem. Soc.113:2722, 1991; Ellman et al., Methods Enzymol. 202:301, 1991; Chung etal., Science 259:806-9, 1993; and Chung et al., Proc. Natl. Acad. Sci.USA 90:10145-9, 1993). In a second method, translation is carried out inXenopus oocytes by microinjection of mutated mRNA and chemicallyaminoacylated suppressor tRNAs (Turcatti et al., J. Biol. Chem.271:19991-8, 1996). Within a third method, E. coli cells are cultured inthe absence of a natural amino acid that is to be replaced (e.g.,phenylalanine) and in the presence of the desired non-naturallyoccurring amino acid(s) (e.g., 2-azaphenylalanine, 3-azaphenylalanine,4-azaphenylalanine, or 4-fluorophenylalanine). The non-naturallyoccurring amino acid is incorporated into the protein in place of itsnatural counterpart. See, Koide et al., Biochem. 33:7470-7476, 1994.Naturally occurring amino acid residues can be converted tonon-naturally occurring species by in vitro chemical modification.Chemical modification can be combined with site-directed mutagenesis tofurther expand the range of substitutions (Wynn and Richards, ProteinSci. 2:395-403, 1993).

A limited number of non-conservative amino acids, amino acids that arenot encoded by the genetic code, non-naturally occurring amino acids,and unnatural amino acids may be substituted for zcytor17 amino acidresidues.

Essential amino acids in the polypeptides of the present invention canbe identified according to procedures known in the art, such assite-directed mutagenesis or alanine-scanning mutagenesis (Cunninghamand Wells, Science 244: 1081-5, 1989; Bass et al., Proc. Natl. Acad.Sci. USA 88:4498-502, 1991). In the latter technique, single alaninemutations are introduced at every residue in the molecule, and theresultant mutant molecules are tested for biological activity (e.g.ligand binding and signal transduction) as disclosed below to identifyamino acid residues that are critical to the activity of the molecule.See also, Hilton et al., J. Biol. Chem. 271:4699-4708, 1996. Sites ofligand-receptor, protein-protein or other biological interaction canalso be determined by physical analysis of structure, as determined bysuch techniques as nuclear magnetic resonance, crystallography, electrondiffraction or photoaffinity labeling, in conjunction with mutation ofputative contact site amino acids. See, for example, de Vos et al.,Science 255:306-312, 1992; Smith et al., J. Mol. Biol. 224:899-904,1992; Wlodaver et al., FEBS Lett. 309:59-64, 1992. The identities ofessential amino acids can also be inferred from analysis of homologieswith related receptors.

Determination of amino acid residues that are within regions or domainsthat are critical to maintaining structural integrity can be determined.Within these regions one can determine specific residues that will bemore or less tolerant of change and maintain the overall tertiarystructure of the molecule. Methods for analyzing sequence structureinclude, but are not limited to, alignment of multiple sequences withhigh amino acid or nucleotide identity and computer analysis usingavailable software (e.g., the Insight II® viewer and homology modelingtools; MSI, San Diego, Calif.), secondary structure propensities, binarypatterns, complementary packing and buried polar interactions (Barton,Current Opin. Struct. Biol. 5:372-376, 1995 and Cordes et al., CurrentOpin. Struct. Biol. 6:3-10, 1996). In general, when designingmodifications to molecules or identifying specific fragmentsdetermination of structure will be accompanied by evaluating activity ofmodified molecules.

Amino acid sequence changes are made in zcytor17 polypeptides so as tominimize disruption of higher order structure essential to biologicalactivity. For example, when the zcytor17 polypeptide comprises one ormore helices, changes in amino acid residues will be made so as not todisrupt the helix geometry and other components of the molecule wherechanges in conformation abate some critical function, for example,binding of the molecule to its binding partners. The effects of aminoacid sequence changes can be predicted by, for example, computermodeling as disclosed above or determined by analysis of crystalstructure (see, e.g., Lapthorn et al., Nat. Struct. Biol. 2:266-268,1995). Other techniques that are well known in the art compare foldingof a variant protein to a standard molecule (e.g., the native protein).For example, comparison of the cysteine pattern in a variant andstandard molecules can be made. Mass spectrometry and chemicalmodification using reduction and alkylation provide methods fordetermining cysteine residues which are associated with disulfide bondsor are free of such associations (Bean et al., Anal. Biochem.201:216-226, 1992; Gray, Protein Sci. 2:1732-1748, 1993; and Pattersonet al., Anal. Chem. 66:3727-3732, 1994). It is generally believed thatif a modified molecule does not have the same disulfide bonding patternas the standard molecule folding would be affected. Another well knownand accepted method for measuring folding is circular dichrosism (CD).Measuring and comparing the CD spectra generated by a modified moleculeand standard molecule is routine (Johnson, Proteins 7:205-214, 1990).Crystallography is another well known method for analyzing folding andstructure. Nuclear magnetic resonance (NMR), digestive peptide mappingand epitope mapping are also known methods for analyzing folding andstructural similarities between proteins and polypeptides (Schaanan etal., Science 257:961-964, 1992).

A Hopp/Woods hydrophilicity profile of the zcytor17 protein sequence asshown in SEQ ID NO:2, SEQ ID NO:46, SEQ ID NO:54, SEQ ID NO:57 and SEQID NO:93 can be generated (Hopp et al., Proc. Natl. Acad. Sci.78:3824-3828, 1981; Hopp, J. Immun. Meth. 88:1-18, 1986 and Triquier etal., Protein Engineering 11:153-169, 1998). See, FIG. 1. The profile isbased on a sliding six-residue window. Buried G, S, and T residues andexposed H, Y, and W residues were ignored. For example, in zcytor17,hydrophilic regions include amino acid residues 43 through 48 of SEQ IDNO:2 and SEQ ID NO:46 (residues 56 through 61 of SEQ ID NO:54), aminoacid residues 157 through 162 of SEQ ID NO:2 and SEQ ID NO:46 (residues170 through 175 of SEQ ID NO:54), amino acid residues 158 through 163 ofSEQ ID NO:2 and SEQ ID NO:46 (residues 171 through 176 of SEQ ID NO:54),amino acid residues 221 through 226 of SEQ ID NO:2 and SEQ ID NO:46(residues 234 through 239 of SEQ ID NO:54), and amino acid residues 426through 431 of SEQ ID NO:2 and SEQ ID NO:46 (residues 439 through 444 ofSEQ ID NO:54).

Those skilled in the art will recognize that hydrophilicity orhydrophobicity will be taken into account when designing modificationsin the amino acid sequence of a zcytor17 polypeptide, so as not todisrupt the overall structural and biological profile. Of particularinterest for replacement are hydrophobic residues selected from thegroup consisting of Val, Leu and Ile or the group consisting of Met,Gly, Ser, Ala, Tyr and Trp. For example, residues tolerant ofsubstitution could include such residues as shown in SEQ ID NO:2, SEQ IDNO:46, SEQ ID NO:54, SEQ ID NO:57 and SEQ ID NO:93. However, Cysteineresidues would be relatively intolerant of substitution.

The identities of essential amino acids can also be inferred fromanalysis of sequence similarity between class I cytokine receptor familymembers with zcytor17. Using methods such as “FASTA” analysis describedpreviously, regions of high similarity are identified within a family ofproteins and used to analyze amino acid sequence for conserved regions.An alternative approach to identifying a variant zcytor17 polynucleotideon the basis of structure is to determine whether a nucleic acidmolecule encoding a potential variant zcytor17 polynucleotide canhybridize to a nucleic acid molecule having the nucleotide sequence ofSEQ ID NO:1, SEQ ID NO:45 or SEQ ID NO:53, as discussed above.

Other methods of identifying essential amino acids in the polypeptidesof the present invention are procedures known in the art, such assite-directed mutagenesis or alanine-scanning mutagenesis (Cunninghamand Wells, Science 244:1081 (1989), Bass et al., Proc. Natl Acad. Sci.USA 88:4498 (1991), Coombs and Corey, “Site-Directed Mutagenesis andProtein Engineering,” in Proteins: Analysis and Design, Angeletti (ed.),pages 259-311 (Academic Press, Inc. 1998)). In the latter technique,single alanine mutations are introduced at every residue in themolecule, and the resultant mutant molecules are tested for biologicalactivity as disclosed below to identify amino acid residues that arecritical to the activity of the molecule. See also, Hilton et al., J.Biol. Chem. 271:4699 (1996).

The present invention also includes functional fragments of zcytor17polypeptides and nucleic acid molecules encoding such functionalfragments. A “functional” zcytor17 or fragment thereof defined herein ischaracterized by its proliferative or differentiating activity, by itsability to induce or inhibit specialized cell functions, or by itsability to bind specifically to an anti-zcytor17 antibody or zcytor17ligand (either soluble or immobilized). Moreover, functional fragmentsalso include the signal peptide, intracellular signaling domain, and thelike. As previously described herein, zcytor17 is characterized by aclass I cytokine receptor structure. Thus, the present invention furtherprovides fusion proteins encompassing: (a) polypeptide moleculescomprising an extracellular domain, cytokine-binding domain, orintracellular domain described herein; and (b) functional fragmentscomprising one or more of these domains. The other polypeptide portionof the fusion protein may be contributed by another class I cytokinereceptor, for example, gp130, LIF, IL-12, WSX-1, IL-2 receptor β-subunitand the β-common receptor (i.e., IL3, IL-5, and GM-CSF receptorβ-subunits), or by a non-native and/or an unrelated secretory signalpeptide that facilitates secretion of the fusion protein.

Routine deletion analyses of nucleic acid molecules can be performed toobtain functional fragments of a nucleic acid molecule that encodes azcytor17 polypeptide. As an illustration, DNA molecules having thenucleotide sequence of SEQ ID NO:1, SEQ ID NO:45 or SEQ ID NO:53 orfragments thereof, can be digested with Bal31 nuclease to obtain aseries of nested deletions. These DNA fragments are then inserted intoexpression vectors in proper reading frame, and the expressedpolypeptides are isolated and tested for zcytor17 activity, or for theability to bind anti-zcytor17 antibodies or zcytor17 ligand. Onealternative to exonuclease digestion is to use oligonucleotide-directedmutagenesis to introduce deletions or stop codons to specify productionof a desired zcytor17 fragment. Alternatively, particular fragments of azcytor17 polynucleotide can be synthesized using the polymerase chainreaction.

Standard methods for identifying functional domains are well-known tothose of skill in the art. For example, studies on the truncation ateither or both termini of interferons have been summarized byHorisberger and Di Marco, Pharmac. Ther. 66:507 (1995). Moreover,standard techniques for functional analysis of proteins are describedby, for example, Treuter et al., Molec. Gen. Genet. 240:113 (1993);Content et al., “Expression and preliminary deletion analysis of the 42kDa 2-5A synthetase induced by human interferon,” in BiologicalInterferon Systems, Proceedings of ISIR-TNO Meeting on InterferonSystems, Cantell (ed.), pages 65-72 (Nijhoff 1987); Herschman, “The EGFReceptor,” in Control of Animal Cell Proliferation 1, Boynton et al.,(eds.) pages 169-199 (Academic Press 1985); Coumailleau et al., J. Biol.Chem. 270:29270 (1995); Fukunaga et al., J. Biol. Chem. 270:25291(1995); Yamaguchi et al., Biochem. Pharmacol. 50:1295 (1995); and Meiselet al., Plant Molec. Biol. 30:1 (1996).

Multiple amino acid substitutions can be made and tested using knownmethods of mutagenesis and screening, such as those disclosed byReidhaar-Olson and Sauer (Science 241:53-57, 1988) or Bowie and Sauer(Proc. Natl. Acad. Sci. USA 86:2152-2156, 1989). Briefly, these authorsdisclose methods for simultaneously randomizing two or more positions ina polypeptide, selecting for functional polypeptide, and then sequencingthe mutagenized polypeptides to determine the spectrum of allowablesubstitutions at each position. Other methods that can be used includephage display (e.g., Lowman et al., Biochem. 30:10832-10837, 1991;Ladner et al., U.S. Pat. No. 5,223,409; Huse, WIPO Publication WO92/062045) and region-directed mutagenesis (Derbyshire et al., Gene46:145, 1986; Ner et al., DNA 7:127, 1988).

Variants of the disclosed zcytor17 DNA and polypeptide sequences can begenerated through DNA shuffling as disclosed by Stemmer, Nature370:389-91, 1994, Stemmer, Proc. Natl. Acad. Sci. USA 91:10747-51, 1994and WIPO Publication WO 97/20078. Briefly, variant DNAs are generated byin vitro homologous recombination by random fragmentation of a parentDNA followed by reassembly using PCR, resulting in randomly introducedpoint mutations. This technique can be modified by using a family ofparent DNAs, such as allelic variants or DNAs from different species, tointroduce additional variability into the process. Selection orscreening for the desired activity, followed by additional iterations ofmutagenesis and assay provides for rapid “evolution” of sequences byselecting for desirable mutations while simultaneously selecting againstdetrimental changes.

Mutagenesis methods as disclosed herein can be combined withhigh-throughput, automated screening methods to detect activity ofcloned, mutagenized zcytor17 receptor polypeptides in host cells.Preferred assays in this regard include cell proliferation assays andbiosensor-based ligand-binding assays, which are described below.Mutagenized DNA molecules that encode active receptors or portionsthereof (e.g., ligand-binding fragments, signaling domains, and thelike) can be recovered from the host cells and rapidly sequenced usingmodern equipment. These methods allow the rapid determination of theimportance of individual amino acid residues in a polypeptide ofinterest, and can be applied to polypeptides of unknown structure.

In addition, the proteins of the present invention (or polypeptidefragments thereof) can be joined to other bioactive molecules,particularly cytokine receptors, to provide multi-functional molecules.For example, one or more domains from zcytor17 soluble receptor can bejoined to other cytokine soluble receptors to enhance their biologicalproperties or efficiency of production.

The present invention thus provides a series of novel, hybrid moleculesin which a segment comprising one or more of the domains of zcytor17 isfused to another polypeptide. Fusion is preferably done by splicing atthe DNA level to allow expression of chimeric molecules in recombinantproduction systems. The resultant molecules are then assayed for suchproperties as improved solubility, improved stability, prolongedclearance half-life, improved expression and secretion levels, andpharmacodynamics. Such hybrid molecules may further comprise additionalamino acid residues (e.g. a polypeptide linker) between the componentproteins or polypeptides.

Using the methods discussed herein, one of ordinary skill in the art canidentify and/or prepare a variety of polypeptide fragments or variantsof SEQ ID NO:2, SEQ ID NO:46, SEQ ID NO:54, SEQ ID NO:57 and SEQ IDNO:93 that retain the signal transduction or ligand binding activity.For example, one can make a zcytor17 “soluble receptor” by preparing avariety of polypeptides that are substantially homologous to thecytokine-binding domain (residues 20 (Ala) to 227 (Pro) of SEQ ID NO:2and SEQ ID NO:46; residues 33 (Ala) to 24o (Pro) of SEQ ID NO:54), theextracellular domain (residues 20 (Ala) to 519 (Glu) of SEQ ID NO:2 andSEQ ID NO:46; residues 33 (Ala) to 532 (Glu) of SEQ ID NO:2), or allelicvariants or species orthologs thereof (e.g., see SEQ ID NO:57 and SEQ IDNO:93 and functional fragments thereof as described herein)) and retainligand-binding activity of the wild-type zcytor17 protein. Moreover,variant zcytor17 soluble receptors such as those shown in SEQ ID NO:18and SEQ ID NO:22 can be isolated. Such polypeptides may includeadditional amino acids from, for example, part or all of thetransmembrane and intracellular domains. Such polypeptides may alsoinclude additional polypeptide segments as generally disclosed hereinsuch as labels, affinity tags, and the like.

For any zcytor17 polypeptide, including variants, soluble receptors, andfusion polypeptides or proteins, one of ordinary skill in the art canreadily generate a fully degenerate polynucleotide sequence encodingthat variant using the information set forth in Tables 1 and 2 above.

The zcytor17 polypeptides of the present invention, includingfull-length polypeptides, biologically active fragments, and fusionpolypeptides, can be produced in genetically engineered host cellsaccording to conventional techniques. Suitable host cells are those celltypes that can be transformed or transfected with exogenous DNA andgrown in culture, and include bacteria, fungal cells, and culturedhigher eukaryotic cells. Eukaryotic cells, particularly cultured cellsof multicellular organisms, are preferred. Techniques for manipulatingcloned DNA molecules and introducing exogenous DNA into a variety ofhost cells are disclosed by Sambrook et al., Molecular Cloning: ALaboratory Manual, 2nd ed., Cold Spring Harbor Laboratory Press, ColdSpring Harbor, N.Y., 1989, and Ausubel et al., eds., Current Protocolsin Molecular Biology, John Wiley and Sons, Inc., NY, 1987.

In general, a DNA sequence encoding a zcytor17 polypeptide is operablylinked to other genetic elements required for its expression, generallyincluding a transcription promoter and terminator, within an expressionvector. The vector will also commonly contain one or more selectablemarkers and one or more origins of replication, although those skilledin the art will recognize that within certain systems selectable markersmay be provided on separate vectors, and replication of the exogenousDNA may be provided by integration into the host cell genome. Selectionof promoters, terminators, selectable markers, vectors and otherelements is a matter of routine design within the level of ordinaryskill in the art. Many such elements are described in the literature andare available through commercial suppliers.

To direct a zcytor17 polypeptide into the secretory pathway of a hostcell, a secretory signal sequence (also known as a leader sequence,prepro sequence or pre sequence) is provided in the expression vector.The secretory signal sequence may be that of zcytor17, or may be derivedfrom another secreted protein (e.g., t-PA) or synthesized de novo. Thesecretory signal sequence is operably linked to the zcytor17 DNAsequence, i.e., the two sequences are joined in the correct readingframe and positioned to direct the newly synthesized polypeptide intothe secretory pathway of the host cell. Secretory signal sequences arecommonly positioned 5′ to the DNA sequence encoding the polypeptide ofinterest, although certain secretory signal sequences may be positionedelsewhere in the DNA sequence of interest (see, e.g., Welch et al., U.S.Pat. No. 5,037,743; Holland et al., U.S. Pat. No. 5,143,830).

Alternatively, the secretory signal sequence contained in thepolypeptides of the present invention is used to direct otherpolypeptides into the secretory pathway. The present invention providesfor such fusion polypeptides. A signal fusion polypeptide can be madewherein a secretory signal sequence derived from amino acid 1 (Met) toamino acid 19 (Ala) of SEQ ID NO:2 and SEQ ID NO:46, or wherein asecretory signal sequence derived from amino acid 1 (Met) to amino acid32 (Ala) of SEQ ID NO:54, or amino acid 1 (Met) to amino acid 45 (Ala)of SEQ ID NO:57 or SEQ ID NO:93), or amino acid 28 (Met) to residue 45(Ala) of SEQ ID NO:57 or SEQ ID NO:93), is operably linked to anotherpolypeptide using methods known in the art and disclosed herein. Thesecretory signal sequence contained in the fusion polypeptides of thepresent invention is preferably fused amino-terminally to an additionalpeptide to direct the additional peptide into the secretory pathway.Such constructs have numerous applications known in the art. Forexample, these novel secretory signal sequence fusion constructs candirect the secretion of an active component of a normally non-secretedprotein. Such fusions may be used in vivo or in vitro to direct peptidesthrough the secretory pathway.

Cultured mammalian cells are suitable hosts within the presentinvention. Methods for introducing exogenous DNA into mammalian hostcells include calcium phosphate-mediated transfection (Wigler et al.,Cell 14:725, 1978; Corsaro and Pearson, Somatic Cell Genetics 7:603,1981: Graham and Van der Eb, Virology 52:456, 1973), electroporation(Neumann et al., EMBO J. 1:841-845, 1982), DEAE-dextran mediatedtransfection (Ausubel et al., ibid.), and liposome-mediated transfection(Hawley-Nelson et al., Focus 15:73, 1993; Ciccarone et al., Focus 15:80,1993, and viral vectors (Miller and Rosman, BioTechniques 7:980-90,1989; Wang and Finer, Nature Med. 2:714-716, 1996). The production ofrecombinant polypeptides in cultured mammalian cells is disclosed, forexample, by Levinson et al., U.S. Pat. No. 4,713,339; Hagen et al., U.S.Pat. No. 4,784,950; Palmiter et al., U.S. Pat. No. 4,579,821; andRingold, U.S. Pat. No. 4,656,134. Suitable cultured mammalian cellsinclude the COS-1 (ATCC No. CRL 1650), COS-7 (ATCC No. CRL 1651), BHK(ATCC No. CRL 1632), BHK 570 (ATCC No. CRL 10314), 293 (ATCC No. CRL1573; Graham et al., J. Gen. Virol. 36:59-72, 1977) and Chinese hamsterovary (e.g. CHO-K1; ATCC No. CCL 61) cell lines. Additional suitablecell lines are known in the art and available from public depositoriessuch as the American Type Culture Collection, Rockville, Md. In general,strong transcription promoters are preferred, such as promoters fromSV-40 or cytomegalovirus. See, e.g., U.S. Pat. No. 4,956,288. Othersuitable promoters include those from metallothionein genes (U.S. Pat.Nos. 4,579,821 and 4,601,978) and the adenovirus major late promoter.

Drug selection is generally used to select for cultured mammalian cellsinto which foreign DNA has been inserted. Such cells are commonlyreferred to as “transfectants”. Cells that have been cultured in thepresence of the selective agent and are able to pass the gene ofinterest to their progeny are referred to as “stable transfectants.” Apreferred selectable marker is a gene encoding resistance to theantibiotic neomycin. Selection is carried out in the presence of aneomycin-type drug, such as G-418 or the like. Selection systems canalso be used to increase the expression level of the gene of interest, aprocess referred to as “amplification.” Amplification is carried out byculturing transfectants in the presence of a low level of the selectiveagent and then increasing the amount of selective agent to select forcells that produce high levels of the products of the introduced genes.A preferred amplifiable selectable marker is dihydrofolate reductase,which confers resistance to methotrexate. Other drug resistance genes(e.g. hygromycin resistance, multi-drug resistance, puromycinacetyltransferase) can also be used. Alternative markers that introducean altered phenotype, such as green fluorescent protein, or cell surfaceproteins such as CD4, CD8, Class I MHC, placental alkaline phosphatasemay be used to sort transfected cells from untransfected cells by suchmeans as FACS sorting or magnetic bead separation technology.

Other higher eukaryotic cells can also be used as hosts, including plantcells, insect cells and avian cells. The use of Agrobacterium rhizogenesas a vector for expressing genes in plant cells has been reviewed bySinkar et al., J. Biosci. (Ban alore) 11:47-58, 1987. Transformation ofinsect cells and production of foreign polypeptides therein is disclosedby Guarino et al., U.S. Pat. No. 5,162,222 and WIPO publication WO94/06463. Insect cells can be infected with recombinant baculovirus,commonly derived from Autographa californica nuclear polyhedrosis virus(AcNPV). See, King, L. A. and Possee, R. D., The Baculovirus ExpressionSystem: A Laboratory Guide, London, Chapman & Hall; O'Reilly, D. R. etal., Baculovirus Expression Vectors: A Laboratory Manual, New York,Oxford University Press., 1994; and, Richardson, C. D., Ed., BaculovirusExpression Protocols. Methods in Molecular Biology, Totowa, N.J., HumanaPress, 1995. A second method of making recombinant zcytor17 baculovirusutilizes a transposon-based system described by Luckow (Luckow, Va., etal., J Virol 67:4566-79, 1993). This system, which utilizes transfervectors, is sold in the Bac-to-Bac™ kit (Life Technologies, Rockville,Md.). This system utilizes a transfer vector, pFastBacl™ (LifeTechnologies) containing a Tn7 transposon to move the DNA encoding thezcytor17 polypeptide into a baculovirus genome maintained in E. coli asa large plasmid called a “bacmid.” See, Hill-Perkins, M. S. and Possee,R. D., J Gen Virol 71:971-6, 1990; Bonning, B. C. et al., J Gen Virol75:1551-6, 1994; and, Chazenbalk, G. D., and Rapoport, B., J Biol Chem270:1543-9, 1995. In addition, transfer vectors can include an in-framefusion with DNA encoding an epitope tag at the C- or N-terminus of theexpressed zcytor17 polypeptide, for example, a Glu-Glu epitope tag(Grussenmeyer, T. et al., Proc. Natl. Acad. Sci. 82:7952-4, 1985). Usinga technique known in the art, a transfer vector containing zcytor17 istransformed into E. Coli, and screened for bacmids which contain aninterrupted lacZ gene indicative of recombinant baculovirus. The bacmidDNA containing the recombinant baculovirus genome is isolated, usingcommon techniques, and used to transfect Spodoptera frugiperda cells,e.g. Sf9 cells. Recombinant virus that expresses zcytor17 issubsequently produced. Recombinant viral stocks are made by methodscommonly used in the art.

The recombinant virus is used to infect host cells, typically a cellline derived from the fall armyworm, Spodoptera frugiperda. See, ingeneral, Glick and Pasternak, Molecular Biotechnology: Principles andApplications of Recombinant DNA, ASM Press, Washington, D. C., 1994.Another suitable cell line is the High FiveO™ cell line (Invitrogen)derived from Trichoplusia ni (U.S. Pat. No. 5,300,435). Commerciallyavailable serum-free media are used to grow and maintain the cells.Suitable media are Sf900 II™ (Life Technologies) or ESF 921™ (ExpressionSystems) for the Sf9 cells; and Ex-cellO405™ (JRH Biosciences, Lenexa,Kans.) or Express FiveO™ (Life Technologies) for the T. ni cells.Procedures used are generally described in available laboratory manuals(King, L. A. and Possee, R. D., ibid.; O'Reilly, D. R. et al., ibid.;Richardson, C. D., ibid.). Subsequent purification of the zcytor17polypeptide from the supernatant can be achieved using methods describedherein.

Fungal cells, including yeast cells, can also be used within the presentinvention. Yeast species of particular interest in this regard includeSaccharomyces cerevisiae, Pichia pastoris, and Pichia methanolica.Methods for transforming S. cerevisiae cells with exogenous DNA andproducing recombinant polypeptides therefrom are disclosed by, forexample, Kawasaki, U.S. Pat. No. 4,599,311; Kawasaki et al., U.S. Pat.No. 4,931,373; Brake, U.S. Pat. No. 4,870,008; Welch et al., U.S. Pat.No. 5,037,743; and Murray et al., U.S. Pat. No. 4,845,075. Transformedcells are selected by phenotype determined by the selectable marker,commonly drug resistance or the ability to grow in the absence of aparticular nutrient (e.g., leucine). A preferred vector system for usein Saccharomyces cerevisiae is the POT1 vector system disclosed byKawasaki et al. (U.S. Pat. No. 4,931,373), which allows transformedcells to be selected by growth in glucose-containing media. Suitablepromoters and terminators for use in yeast include those from glycolyticenzyme genes (see, e.g., Kawasaki, U.S. Pat. No. 4,599,311; Kingsman etal., U.S. Pat. No. 4,615,974; and Bitter, U.S. Pat. No. 4,977,092) andalcohol dehydrogenase genes. See also U.S. Pat. Nos. 4,990,446;5,063,154; 5,139,936 and 4,661,454. Transformation systems for otheryeasts, including Hansenula polymorpha, Schizosaccharomyces pombe,Kluyveromyces lactis, Kluyveromyces fragilis, Ustilago maydis, Pichiapastoris, Pichia methanolica, Pichia guillermondii and Candida maltosaare known in the art. See, for example, Gleeson et al., J. Gen.Microbiol. 132:3459-3465, 1986 and Cregg, U.S. Pat. No. 4,882,279.Aspergillus cells may be utilized according to the methods of McKnightet al., U.S. Pat. No. 4,935,349. Methods for transforming Acremoniumchrysogenum are disclosed by Sumino et al., U.S. Pat. No. 5,162,228.Methods for transforming Neurospora are disclosed by Lambowitz, U.S.Pat. No. 4,486,533.

The use of Pichia methanolica as host for the production of recombinantproteins is disclosed in WIPO Publications WO 97/17450, WO 97/17451, WO98/02536, and WO 98/02565. DNA molecules for use in transforming P.methanolica will commonly be prepared as double-stranded, circularplasmids, which are preferably linearized prior to transformation. Forpolypeptide production in P. methanolica, it is preferred that thepromoter and terminator in the plasmid be that of a P. methanolica gene,such as a P. methanolica alcohol utilization gene (AUG1 or AUG2). Otheruseful promoters include those of the dihydroxyacetone synthase (DHAS),formate dehydrogenase (FMD), and catalase (CAT) genes. To facilitateintegration of the DNA into the host chromosome, it is preferred to havethe entire expression segment of the plasmid flanked at both ends byhost DNA sequences. A preferred selectable marker for use in Pichiamethanolica is a P. methanolica ADE2 gene, which encodesphosphoribosyl-5-aminoimidazole carboxylase (AIRC; EC 4.1.1.21), whichallows ade2 host cells to grow in the absence of adenine. Forlarge-scale, industrial processes where it is desirable to minimize theuse of methanol, it is preferred to use host cells in which bothmethanol utilization genes (AUG1 and AUG2) are deleted. For productionof secreted proteins, host cells deficient in vacuolar protease genes(PEP4 and PRB1) are preferred. Electroporation is used to facilitate theintroduction of a plasmid containing DNA encoding a polypeptide ofinterest into P. methanolica cells. It is preferred to transform P.methanolica cells by electroporation using an exponentially decaying,pulsed electric field having a field strength of from 2.5 to 4.5 kV/cm,preferably about 3.75 kV/cm, and a time constant (t) of from 1 to 40milliseconds, most preferably about 20 milliseconds.

Prokaryotic host cells, including strains of the bacteria Escherichiacoli, Bacillus and other genera are also useful host cells within thepresent invention. Techniques for transforming these hosts andexpressing foreign DNA sequences cloned therein are well known in theart (see, e.g., Sambrook et al., ibid.). When expressing a zcytor17polypeptide in bacteria such as E. coli, the polypeptide may be retainedin the cytoplasm, typically as insoluble granules, or may be directed tothe periplasmic space by a bacterial secretion sequence. In the formercase, the cells are lysed, and the granules are recovered and denaturedusing, for example, guanidine isothiocyanate or urea. The denaturedpolypeptide can then be refolded and dimerized by diluting thedenaturant, such as by dialysis against a solution of urea and acombination of reduced and oxidized glutathione, followed by dialysisagainst a buffered saline solution. In the latter case, the polypeptidecan be recovered from the periplasmic space in a soluble and functionalform by disrupting the cells (by, for example, sonication or osmoticshock) to release the contents of the periplasmic space and recoveringthe protein, thereby obviating the need for denaturation and refolding.

Transformed or transfected host cells are cultured according toconventional procedures in a culture medium containing nutrients andother components required for the growth of the chosen host cells. Avariety of suitable media, including defined media and complex media,are known in the art and generally include a carbon source, a nitrogensource, essential amino acids, vitamins and minerals. Media may alsocontain such components as growth factors or serum, as required. Thegrowth medium will generally select for cells containing the exogenouslyadded DNA by, for example, drug selection or deficiency in an essentialnutrient which is complemented by the selectable marker carried on theexpression vector or co-transfected into the host cell. P. methanolicacells are cultured in a medium comprising adequate sources of carbon,nitrogen and trace nutrients at a temperature of about 25° C. to 35° C.Liquid cultures are provided with sufficient aeration by conventionalmeans, such as shaking of small flasks or sparging of fermentors. Apreferred culture medium for P. methanolica is YEPD (2% D-glucose, 2%Bacto™ Peptone (Difco Laboratories, Detroit, Mich.), 1% Bacto™ yeastextract (Difco Laboratories), 0.004% adenine and 0.006% L-leucine).

Within one aspect of the present invention, a zcytor17 cytokine receptor(including transmembrane and intracellular domains) is produced by acultured cell, and the cell is used to screen for ligands for thereceptor, including the natural ligand, as well as agonists andantagonists of the natural ligand. To summarize this approach, a cDNA orgene encoding the receptor is combined with other genetic elementsrequired for its expression (e.g., a transcription promoter), and theresulting expression vector is inserted into a host cell. Cells thatexpress the DNA and produce functional receptor are selected and usedwithin a variety of screening systems.

Mammalian cells suitable for use in expressing the novel receptors ofthe present invention and transducing a receptor-mediated signal includecells that express β-subunit, such as gp130, and cells that co-expressgp310 and LIF receptor (Gearing et al., EMBO J. 10:2839-2848, 1991;Gearing et al., U.S. Pat. No. 5,284,755). In this regard it is generallypreferred to employ a cell that is responsive to other cytokines thatbind to receptors in the same subfamily, such as IL-6 or LIF, becausesuch cells will contain the requisite signal transduction pathway(s).Preferred cells of this type include BaF3 cells (Palacios and Steinmetz,Cell 41: 727-734, 1985; Mathey-Prevot et al., Mol. Cell. Biol. 6:4133-4135, 1986), the human TF-1 cell line (ATCC number CRL-2003) andthe DA-1 cell line (Branch et al., Blood 69:1782, 1987; Broudy et al.,Blood 75:1622-1626, 1990). In the alternative, suitable host cells canbe engineered to produce a β-subunit or other cellular component neededfor the desired cellular response. For example, the murine cell lineBaF3 (Palacios and Steinmetz, Cell 41:727-734, 1985; Mathey-Prevot etal., Mol. Cell. Biol. 6: 4133-4135, 1986), a baby hamster kidney (BHK)cell line, or the CTLL-2 cell line (ATCC TIB-214) can be transfected toexpress the mouse gp130 subunit, or mouse gp130 and LIF receptor, inaddition to zcytor17. It is generally preferred to use a host cell andreceptor(s) from the same species, however this approach allows celllines to be engineered to express multiple receptor subunits from anyspecies, thereby overcoming potential limitations arising from speciesspecificity. In the alternative, species homologs of the human receptorcDNA can be cloned and used within cell lines from the same species,such as a mouse cDNA in the BaF3 cell, line. Cell lines that aredependent upon one hematopoietic growth factor, such as IL-3, can thusbe engineered to become dependent upon a zcytor17 ligand oranti-zcytor17 antibody.

Cells expressing functional zcytor17 are used within screening assays. Avariety of suitable assays are known in the art. These assays are basedon the detection of a biological response in the target cell. One suchassay is a cell proliferation assay. Cells are cultured in the presenceor absence of a test compound, and cell proliferation is detected by,for example, measuring incorporation of tritiated thymidine or bycalorimetric assay based on the reduction or metabolic breakdown ofAlymar Blue™ (AccuMed, Chicago, Ill.) or3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)(Mosman, J. Immunol. Meth. 65: 55-63, 1983). An alternative assay formatuses cells that are further engineered to express a reporter gene. Thereporter gene is linked to a promoter element that is responsive to thereceptor-linked pathway, and the assay detects activation oftranscription of the reporter gene. A preferred promoter element in thisregard is a serum response element, STAT or SRE (see, for example, Shawet al., Cell 56:563-572, 1989). A preferred such reporter gene is aluciferase gene (de Wet et al., Mol. Cell. Biol. 7:725, 1987).Expression of the luciferase gene is detected by luminescence usingmethods known in the art (e.g., Baumgartner et al., J. Biol. Chem.269:19094-29101, 1994; Schenborn and Goiffin, Promega Notes 41:11,1993). Luciferase assay kits are commercially available from, forexample, Promega Corp., Madison, Wis. Target cell lines of this type canbe used to screen libraries of chemicals, cell-conditioned culturemedia, fungal broths, soil samples, water samples, and the like. Forexample, a bank of cell- or tissue-conditioned media samples can beassayed on a target cell to identify cells that produce ligand. Positivecells are then used to produce a cDNA library in a mammalian cellexpression vector, which is divided into pools, transfected into hostcells, and expressed. Media samples from the transfected cells are thenassayed, with subsequent division of pools, retransfection,subculturing, and re-assay of positive cells to isolate a clonal cellline expressing the ligand. Media samples conditioned by kidney, liver,spleen, thymus, other lymphoid tissues, or T-cells are preferred sourcesof ligand for use in screening procedures.

A natural ligand for zcytor17 can also be identified by mutagenizing acytokine-dependent cell line expressing zcytor17 and culturing it underconditions that select for autocrine growth. See WIPO publication WO95/21930. Within a typical procedure, cells expressing zcytor17 aremutagenized, such as with EMS. The cells are then allowed to recover inthe presence of the required cytokine, then transferred to a culturemedium lacking the cytokine. Surviving cells are screened for theproduction of a ligand for zcytor17, such as by adding soluble receptorpolypeptide comprising the zcytor17 cytokine-binding domain describedherein to the culture medium to compete against the ligand or byassaying conditioned media on wild-type cells compared to transfectedcells expressing the zcytor17 receptor. Preferred cell lines for usewithin this method include cells that are transfected to express gp130or gp130 in combination with LIF receptor. Preferred such host celllines include transfected CTLL-2 cells (Gillis and Smith, Nature268:154-156, 1977) and transfected BaF3 cells.

Moreover, a secretion trap method employing zcytor17 soluble receptorpolypeptide can be used to isolate a zcytor17 ligand (Aldrich, et al,Cell 87: 1161-1169, 1996). A cDNA expression library prepared from aknown or suspected ligand source is transfected into COS-7 cells. ThecDNA library vector generally has an SV40 origin for amplification inCOS-7 cells, and a CMV promoter for high expression. The transfectedCOS-7 cells are grown in a monolayer and then fixed and permeabilized.Tagged or biotin-labeled zcytor17 soluble receptor, described herein, isthen placed in contact with the cell layer and allowed to bind cells inthe monolayer that express an anti-complementary molecule, i.e., azcytor17 ligand. A cell expressing a ligand will thus be bound withreceptor molecules. An anti-tag antibody (anti-Ig for Ig fusions, M2 oranti-FLAG for FLAG-tagged fusions, streptavidin, anti-Glu-Glu tag, andthe like) which is conjugated with horseradish peroxidase (HRP) is usedto visualize these cells to which the tagged or biotin-labeled zcytor17soluble receptor has bound. The HRP catalyzes deposition of a tyramidereagent, for example, tyramide-FITC. A commercially-available kit can beused for this detection (for example, Renaissance TSA-Direct™ Kit; NENLife Science Products, Boston, Mass.). Cells which express zcytor17receptor ligand will be identified under fluorescence microscopy asgreen cells and picked for subsequent cloning of the ligand usingprocedures for plasmid rescue as outlined in Aldrich, et al, supra.,followed by subsequent rounds of secretion trap assay, or conventionalscreening of cDNA library pools, until single clones are identified.

As a receptor, the activity of zcytor17 polypeptide can be measured by asilicon-based biosensor microphysiometer which measures theextracellular acidification rate or proton excretion associated withreceptor binding and subsequent physiologic cellular responses. Anexemplary device is the Cytosensor™ Microphysiometer manufactured byMolecular Devices, Sunnyvale, Calif. A variety of cellular responses,such as cell proliferation, ion transport, energy production,inflammatory response, regulatory and receptor activation, and the like,can be measured by this method. See, for example, McConnell, H. M. etal., Science 257:1906-1912, 1992; Pitchford, S. et al., Meth. Enzymol.228:84-108, 1997; Arimilli, S. et al., J. Immunol. Meth. 212:49-59,1998; Van Liefde, I. Et al., Eur. J. Pharmacol. 346:87-95, 1998. Themicrophysiometer can be used for assaying eukaryotic, prokaryotic,adherent or non-adherent cells. By measuring extracellular acidificationchanges in cell media over time, the microphysiometer directly measurescellular responses to various stimuli, including agonists, ligands, orantagonists of the zcytor17 polypeptide. Preferably, themicrophysiometer is used to measure responses of a zcytor17-expressingeukaryotic cell, compared to a control eukaryotic cell that does notexpress zcytor17 polypeptide. Zcytor17-expressing eukaryotic cellscomprise cells into which zcytor17 has been transfected or infected viaadenovirus vector, and the like, as described herein, creating a cellthat is responsive to zcytor17-modulating stimuli, or are cellsnaturally expressing zcytor17, such as zcytor17-expressing cells derivedfrom lymphoid, spleen, thymus tissue or PBLs. Differences, measured byan increase or decrease in extracellular acidification, in the responseof cells expressing zcytor17, relative to a control, are a directmeasurement of zcytor17-modulated cellular responses. Moreover, suchzcytor17-modulated responses can be assayed under a variety of stimuli.Also, using the microphysiometer, there is provided a method ofidentifying agonists and antagonists of zcytor17 polypeptide, comprisingproviding cells expressing a zcytor17 polypeptide, culturing a firstportion of the cells in the absence of a test compound, culturing asecond portion of the cells in the presence of a test compound, anddetecting an increase or a decrease in a cellular response of the secondportion of the cells as compared to the first portion of the cells.Antagonists and agonists, including the natural ligand for zcytor17polypeptide, can be rapidly identified using this method.

Additional assays provided by the present invention include the use ofhybrid receptor polypeptides. These hybrid polypeptides fall into twogeneral classes. Within the first class, the intracellular domain ofzcytor17, comprising approximately residues 544 (Lys) to 732 (Val) ofSEQ ID NO:2, residues 544 (Lys) to 649 (Ile) of SEQ ID NO:46, orresidues 557 (Lys) to 662 (Ile) of SEQ ID NO:54, or residues 551 (Lys)to 662 (Cys) of SEQ ID NO:57 is joined to the ligand-binding domain of asecond receptor. It is preferred that the second receptor be ahematopoietic cytokine receptor, such as mpl receptor (Souyri et al.,Cell 63:1137-1147, 1990). The hybrid receptor will further comprise atransmembrane domain, which may be derived from either receptor. A DNAconstruct encoding the hybrid receptor is then inserted into a hostcell. Cells expressing the hybrid receptor are cultured in the presenceof a ligand for the binding domain and assayed for a response. Thissystem provides a means for analyzing signal transduction mediated byzcytor17 while using readily available ligands. This system can also beused to determine if particular cell lines are capable of responding tosignals transduced by zcytor17. A second class of hybrid receptorpolypeptides comprise the extracellular (ligand-binding) domain(approximately residues 20 (Ala) to 519 (Glu) of SEQ ID NO:2 and SEQ IDNO:46; approximately residues 33 (Ala) to 532 (Glu) of SEQ ID NO:54) orcytokine-binding domain of zcytor17 (approximately residues 20 (Ala) to227 (Pro) of SEQ ID NO:2 and SEQ ID NO:46; or approximately residues 33(Ala) to 240 (Pro) of SEQ ID NO:54; approximately residues 46 (Val) to533 (Glu) of SEQ ID NO:57; or approximately residues 46 (Val) to 533(Trp) of SEQ ID NO:93) with a cytoplasmic domain of a second receptor,preferably a cytokine receptor, and a transmembrane domain. Thetransmembrane domain may be derived from either receptor. Hybridreceptors of this second class are expressed in cells known to becapable of responding to signals transduced by the second receptor.Together, these two classes of hybrid receptors enable the use of abroad spectrum of cell types within receptor-based assay systems.

Cells found to express a ligand for zcytor17 are then used to prepare acDNA library from which the ligand-encoding cDNA may be isolated asdisclosed above. The present invention thus provides, in addition tonovel receptor polypeptides, methods for cloning polypeptide ligands forthe receptors.

The zcytor17 structure and tissue expression suggests a role in earlyhematopoietic or thymocyte development and immune response regulation orinflammation. These processes involve stimulation of cell proliferationand differentiation in response to the binding of one or more cytokinesto their cognate receptors. In view of the tissue distribution observedfor this receptor, agonists (including the natural ligand) andantagonists have enormous potential in both in vitro and in vivoapplications. Compounds identified as receptor agonists are useful forstimulating proliferation and development of target cells in vitro andin vivo. For example, agonist compounds or antizcytor17 antibodies, areuseful as components of defined cell culture media, and may be usedalone or in combination with other cytokines and hormones to replaceserum that is commonly used in cell culture. Agonists are thus useful inspecifically promoting the growth and/or development or activation ofmonocytes, T-cells, B-cells, and other cells of the lymphoid and myeloidlineages, and hematopoietic cells in culture.

Agonist ligands for zcytor17, or anti-zcytor17 antibodies and bindingpartners, may be useful in stimulating cell-mediated immunity and forstimulating lymphocyte proliferation, such as in the treatment ofinfections involving immunosuppression, including certain viralinfections. Additional uses include tumor suppression, where malignanttransformation results in tumor cells that are antigenic. Agonistligands or anti-zcytor17 antibodies and binding partners could be usedto induce cytotoxicity, which may be mediated through activation ofeffector cells such as T-cells, NK (natural killer) cells, or LAK(lymphoid activated killer) cells, or induced directly through apoptoticpathways. Agonist ligands, anti-zcytor17 antibodies and binding partnersmay also be useful in treating leukopenias by increasing the levels ofthe affected cell type, and for enhancing the regeneration of the T-cellrepertoire after bone marrow transplantation; or for enhancing monocyteproliferation or activation, and for diagnostic and other uses describedherein.

Antagonist ligands, compounds, or anti-zcytor17 antibodies may findutility in the suppression of the immune system, such as in thetreatment of autoimmune diseases, including rheumatoid arthritis,multiple sclerosis, diabetes mellitis, inflammatory bowel disease,Crohn's disease, etc. Immune suppression can also be used to reducerejection of tissue or organ transplants and grafts and to treat T-cell,B-cell or monocyte-specific leukemias or lymphomas, and other immunecell cancers, by inhibiting proliferation of the affected cell type.Moreover zcytor17 polynucleotides, anti-zcytor17 antibodies and bindingpartners can be used to detect monocytes, and aid in the diagnosis ofsuch autoimmuine disease, particularly in disease states where monocytesare elevated or activated.

Zcytor17 polypeptides may also be used within diagnostic systems for thedetection of circulating levels of ligand. Within a related embodiment,antibodies or other agents that specifically bind to zcytor17 receptorpolypeptides can be used to detect circulating receptor polypeptides.Zcytor17 appears to be naturally-expressed as a soluble receptor asshown by the soluble receptor forms shown in SEQ ID NO: 18 and SEQ IDNO:22. Elevated or depressed levels of ligand or receptor polypeptidesmay be indicative of pathological conditions, including cancer. Solublereceptor polypeptides may contribute to pathologic processes and can bean indirect marker of an underlying disease. For example, elevatedlevels of soluble IL-2 receptor in human serum have been associated witha wide variety of inflammatory and neoplastic conditions, such asmyocardial infarction, asthma, myasthenia gravis, rheumatoid arthritis,acute T-cell leukemia, B-cell lymphomas, chronic lymphocytic leukemia,colon cancer, breast cancer, and ovarian cancer (Heaney et al., Blood87:847-857, 1996). Similarly, zcytor17 is elevated in activatedmonocytes, and hence zcytor17 and/or its soluble receptors may beassociated with or serve as a marker for inflammatory and neoplasticconditions associated therewith.

A ligand-binding polypeptide of a zcytor17 receptor, or “solublereceptor,” can be prepared by expressing a truncated DNA encoding thezcytor17 cytokine binding domain (approximately residue 20 (Ala) throughresidue 227 (Pro) of the human receptor SEQ ID NO:2 and SEQ ID NO:46;approximately residue 33 (Ala) through residue 240 (Pro) of the humanreceptor SEQ ID NO:54), or the extracellular domain (approximatelyresidue 20 (Ala) through residue 519 (Glu) of SEQ ID NO:2 and SEQ IDNO:46; approximately residue 33 (Ala) through residue 532 (Glu) of SEQID NO:54), or the corresponding region of a non-human receptor, e.g.,such as the corresponding regions described herein for SEQ ID NO:57 andSEQ ID NO:93. It is preferred that the extracellular domain be preparedin a form substantially free of transmembrane and intracellularpolypeptide segments. Moreover, ligand-binding polypeptide fragmentswithin the zcytor17 cytokine binding domain, described above, can alsoserve as zcytor17 soluble receptors for uses described herein. To directthe export of a receptor polypeptide from the host cell, the receptorDNA is linked to a second DNA segment encoding a secretory peptide, suchas a t-PA secretory peptide or a zcytor17 secretory peptide. Tofacilitate purification of the secreted receptor polypeptide, aC-terminal extension, such as a poly-histidine tag, Glu-Glu tag peptide,substance P, Flag™ peptide (Hopp et al., Bio/Technology 6:1204-1210,1988; available from Eastman Kodak Co., New Haven, Conn.) or anotherpolypeptide or protein for which an antibody or other specific bindingagent is available, can be fused to the receptor polypeptide.

In an alternative approach, a receptor extracellular domain can beexpressed as a fusion with immunoglobulin heavy chain constant regions,typically an F_(C) fragment (e.g., Fc4), which contains two constantregion domains and lacks the variable region. Such fusions are typicallysecreted as multimeric molecules wherein the Fc portions are disulfidebonded to each other and two receptor polypeptides are arrayed in closeproximity to each other. Fusions of this type can be used to affinitypurify the cognate ligand from solution, as an in vitro assay tool, toblock signals in vitro by specifically titrating out ligand, and asantagonists in vivo by administering them parenterally to bindcirculating ligand and clear it from the circulation. To purify ligand,a zcytor17-Ig chimera is added to a sample containing the ligand (e.g.,cell-conditioned culture media or tissue extracts) under conditions thatfacilitate receptor-ligand binding (typically near-physiologicaltemperature, pH, and ionic strength). The chimera-ligand complex is thenseparated by the mixture using protein A, which is immobilized on asolid support (e.g., insoluble resin beads). The ligand is then elutedusing conventional chemical techniques, such as with a salt or pHgradient. In the alternative, the chimera itself can be bound to a solidsupport, with binding and elution carried out as above. Collectedfractions can be re-fractionated until the desired level of purity isreached.

Moreover, zcytor17 soluble receptors can be used as a “ligand sink,”i.e., antagonist, to bind ligand in vivo or in vitro in therapeutic orother applications where the presence of the ligand is not desired. Forexample, in cancers that are expressing large amount of bioactivezcytor17 ligand, zcytor17 soluble receptors can be used as a directantagonist of the ligand in vivo, and may aid in reducing progressionand symptoms associated with the disease. Moreover, zcytor17 solublereceptor can be used to slow the progression of cancers thatover-express zcytor17 receptors, by binding ligand in vivo that wouldotherwise enhance proliferation of those cancers. Similar in vitroapplications for a zcytor17 soluble receptor can be used, for instance,as a negative selection to select cell lines that grow in the absence ofzcytor17 ligand.

Moreover, zcytor17 soluble receptor can be used in vivo or in diagnosticapplications to detect zcytor17 ligand-expressing cancers in vivo or intissue samples. For example, the zcytor17 soluble receptor can beconjugated to a radio-label or fluorescent label as described herein,and used to detect the presence of the ligand in a tissue sample usingan in vitro ligand-receptor type binding assay, or fluorescent imagingassay. Moreover, a radiolabeled zcytor17 soluble receptor could beadministered in vivo to detect ligand-expressing solid tumors through aradio-imaging method known in the art.

The molecules of the present invention have particular use in themonocyte/macrophage arm of the immune system. For example, interferongamma (IFNγ) is a potent activator of mononuclear phagocytes. Theincrease in expression of zcytor17 upon activation of THP-1 cells (ATCCNo. TIB-202) with interferon gamma suggests that this receptor isinvolved in monocyte activation. Monocytes are incompletelydifferentiated cells that migrate to various tissues where they matureand become macrophages. Macrophages play a central role in the immuneresponse by presenting antigen to lymphocytes and play a supportive roleas accessory cells to lymphocytes by secreting numerous cytokines.Macrophages can internalize extracellular molecules and upon activationhave an increased ability to kill intracellular microorganisms and tumorcells. Activated macrophages are also involved in stimulating acute orlocal inflammation. Moreover, monocyte-macrophage function has beenshown to be abnormal in a variety of diseased states. For example see,Johnston, R B, New Eng. J. Med. 318:747-752, 1998.

One of skill in the art would recognize that agonists of zcytor17 areuseful. For example, depressed migration of monocytes has been reportedin populations with a predisposition to infection, such as newborninfants, patients receiving corticosteroid or other immunosuppressivetherapy, and patients with diabetes mellitus, burns, or AIDS. Agonistsfor zcytor17, such as anti-zcytor17 antibodies and binding partners, aswell as the natural ligand, could result in an increase in ability ofmonocytes to migrate and possibly prevent infection in thesepopulations. There is also a profound defect of phagocytic killing bymononuclear phagocytes from patients with chronic granulomatous disease.This results in the formation of subcutaneous abscesses, as well asabscesses in the liver, lungs, spleen, and lymph nodes. An agonist ofzcytor17 such as anti-zcytor17 antibodies and binding partners, as wellas the natural ligand, could correct or improve this phagocytic defect.In addition, defective monocyte cytotoxicity has been reported inpatients with cancer and Wiskott-Aldrich syndrome (eczema,thrombocytopenia, and recurrent infections). Activation of monocytes byagonists of zcytor17 such as anti-zcytor17 antibodies and bindingpartners, as well as the natural ligand, could aid in treatment of theseconditions. The monocyte-macrophage system is prominently involved inseveral lipid-storage diseases (sphingolipidoses) such as Gaucher'sdisease. Resistance to infection can be impaired because of a defect inmacrophage function, which could be treated by agonists to zcytor17 suchas anti-zcytor17 antibodies and binding partners, as well as the naturalligand.

Moreover, one of skill in the art would recognize that antagonists ofzcytor17 are useful. For example, in atherosclerotic lesions, one of thefirst abnormalities is localization of monocyte/macrophages toendothelial cells. These lesions could be prevented by use ofantagonists to zcytor17. Anti-zcytor17 antibodies and binding partnerscan also be used as antagonists to the natural ligand of zcytor17.Moreover, monoblastic leukemia is associated with a variety of clinicalabnormalities that reflect the release of the biologic products of themacrophage, examples include high levels of lysozyme in the serum andurine and high fevers. Moreover, such leukemias exhibit an abnormalincrease of monocytic cells. These effects could possibly be preventedby antagonists to zcytor17, such as described herein. Moreover,anti-zcytor17 antibodies and binding partners can be conjugated tomolecules such as toxic moieties and cytokines, as described herein todirect the killing of leukemia monocytic cells.

Using methods known in the art, and disclosed herein, one of skill couldreadily assess the activity of zcytor17 agonists and antagonists in thedisease states disclosed herein, inflammation, cancer, or infection aswell as other disease states involving monocytic cells. In addition, aszcytor17 is expressed in a monocyte-specific manner, and these diseasesinvolve abnormalities in monocytic cells, such as cell proliferation,function, localization, and activation, the polynucleotides,polypeptides, and antibodies of the present invention can be used to asdiagnostics to detect such monocytic cell abnormalities, and indicatethe presence of disease. Such methods involve taking a biological samplefrom a patient, such as blood, saliva, or biopsy, and comparing it to anormal control sample. Histological, cytological, flow cytometric,biochemical and other methods can be used to determine the relativelevels or localization of zcytor17, or cells expressing zcytor17, i.e.,monocytes, in the patient sample compared to the normal control. Achange in the level (increase or decrease) of zcytor17 expression, or achange in number or localization of monocytes (e.g., increase orinfiltration of monocytic cells in tissues where they are not normallypresent) compared to a control would be indicative of disease. Suchdiagnostic methods can also include using radiometric, fluorescent, andcolorimetric tags attached to polynucleotides, polypeptides orantibodies of the present invention. Such methods are well known in theart and disclosed herein.

Amino acid sequences having Zcytor17 activity can be used to modulatethe immune system by binding Zcytor17 ligand, and thus, preventing thebinding of Zcytor17 ligand with endogenous Zcytor17 receptor. Zcytor17antagonists, such as anti-Zcytor17 antibodies, can also be used tomodulate the immune system by inhibiting the binding of Zcytor17 ligandwith the endogenous Zcytor17 receptor. Accordingly, the presentinvention includes the use of proteins, polypeptides, and peptideshaving Zcytor17 activity (such as Zcytor17 polypeptides, Zcytor17analogs (e.g., anti-Zcytor17 anti-idiotype antibodies), and Zcytor17fusion proteins) to a subject which lacks an adequate amount of thispolypeptide, or which produces an excess of Zcytor17 ligand. Zcytor17antagonists (e.g., anti-Zcytor17 antibodies) can be also used to treat asubject which produces an excess of either Zcytor17 ligand or Zcytor71.Suitable subjects include mammals, such as humans.

Zcytor17 has been shown to be upregulated in monocyte cells, and may beinvolved in regulating inflammation. As such, polypeptides of thepresent invention can be assayed and used for their ability to modifyinflammation, or can be used as a marker for inflammation. Methods todetermine proinflammatory and antiinflammatory qualities of zcytor17 areknown in the art and discussed herein. Moreover, it may be involved inup-regulating the production of acute phase reactants, such as serumamyloid A (SAA), α1-antichymotrypsin, and haptoglobin, and thatexpression of zcytor17 ligand may be increased upon injection oflipopolysaccharide (LPS) in vivo that are involved in inflammatoryresponse (Dumoutier, L. et al., Proc. Nat'l. Acad. Sci. 97:10144-10149,2000). Production of acute phase proteins, such as SAA, is considered sshort-term survival mechanism where inflammation is beneficial; however,maintenance of acute phase proteins for longer periods contributes tochronic inflammation and can be harmful to human health. For review, seeUhlar, C M and Whitehead, A S, Eur. J. Biochem. 265:501-523, 1999, andBaumann H. and Gauldie, J. Immunology Today 15:74-80, 1994. Moreover,the acute phase protein SAA is implicated in the pathogenesis of severalchronic inflammatory diseases, is implicated in atherosclerosis andrheumatoid arthritis, and is the precursor to the amyloid A proteindeposited in amyloidosis (Uhlar, C M and Whitehead, supra.). Thus, wherea ligand for zcytor17 that acts as a pro-inflammatory molecule andinduces production of SAA, antagonists would be useful in treatinginflammatory disease and other diseases associated with acute phaseresponse proteins induced by the ligand. Such antagonists are providedby the present invention. For example, a method of reducing inflammationcomprises administering to a mammal with inflammation an amount of acomposition of soluble zcytor17-comprising receptor, or anti-zcytor17antibody that is sufficient to reduce inflammation. Moreover, a methodof suppressing an inflammatory response in a mammal with inflammationcan comprise: (1) determining a level of serum amyloid A protein; (2)administering a composition comprising a soluble zcytor17 cytokinereceptor polypeptide as described herein in an acceptable pharmaceuticalvehicle; (3) determining a post administration level of serum amyloid Aprotein; (4) comparing the level of serum amyloid A protein in step (1)to the level of serum amyloid A protein in step (3), wherein a lack ofincrease or a decrease in serum amyloid A protein level is indicative ofsuppressing an inflammatory response.

The receptors of the present invention include at least one zcytor17receptor subunit. A second receptor polypeptide included in theheterodimeric soluble receptor belongs to the receptor subfamily thatincludes class I cytokine receptor subunits. According to the presentinvention, in addition to a monomeric or homodimeric zcytor17 receptorpolypeptide, a heterodimeric soluble zcytor17 receptor, as exemplifiedby an embodiment comprising a soluble zcytor17 receptor+ soluble Class Ireceptor heterodimeric component, can act as an antagonist of thenatural zcytor17 ligand. Other embodiments include soluble multimericreceptors comprising zcytor17.

Analysis of the tissue distribution of the mRNA corresponding zcytor17cDNA showed that mRNA level was highest in monocytes and prostate cells,and is elevated in activated monocytes, and activated CD4+, activatedCD8+, and activated CD3+ cells. Hence, zcytor17 is implicated ininducing inflammatory and immune response. Thus, particular embodimentsof the present invention are directed toward use of soluble zcytor17heterodimers as antagonists in inflammatory and immune diseases orconditions such as pancreatitis, type I diabetes (IDDM), pancreaticcancer, pancreatitis, Graves Disease, inflammatory bowel disease (IBD),Crohn's Disease, colon and intestinal cancer, diverticulosis, autoimmunedisease, sepsis, organ or bone marrow transplant; inflammation due totrauma, surgery or infection; amyloidosis; splenomegaly; graft versushost disease; and where inhibition of inflammation, immune suppression,reduction of proliferation of hematopoietic, immune, inflammatory orlymphoid cells, macrophages, T-cells (including Th1 and Th2 cells, CD4+and CD8+ cells), suppression of immune response to a pathogen orantigen. Moreover the presence of zcytor178 expression in activatedimmune cells such as activated CD4+ and CD19+ cells showed that zcytor17may be involved in the body's immune defensive reactions against foreigninvaders: such as microorganisms and cell debris, and could play a rolein immune responses during inflammation and cancer formation. As such,antibodies and bidning partners of the present invention that areagonistic or antagonistic to zcytor17 function, can be used to modifyimmune response and inflammation.

Moreover, antibodies or binding polypeptides that bind zcytor17polypeptides, monomers, homodimers, heterodimers and multimers describedherein and/or zcytor17 polypeptides, monomers, homodimers, heterodimersand multimers themselves are useful to:

1) Antagonize or block signaling via the zcytor17 receptors in thetreatment of acute inflammation, inflammation as a result of trauma,tissue injury, surgery, sepsis or infection, and chronic inflammatorydiseases such as asthma, inflammatory bowel disease (IBD), chroniccolitis, splenomegaly, rheumatoid arthritis, recurrent acuteinflammatory episodes (e.g., tuberculosis), and treatment ofamyloidosis, and atherosclerosis, Castleman's Disease, asthma, and otherdiseases associated with the induction of acute-phase response.

2) Antagonize or block signaling via the zcytor17 receptors in thetreatment of autoimmune diseases such as IDDM, multiple sclerosis (MS),systemic Lupus erythematosus (SLE), myasthenia gravis, rheumatoidarthritis, and IBD to prevent or inhibit signaling in immune cells (e.g.lymphocytes, monocytes, leukocytes) via zcytor17 (Hughes C et al., J.Immunol 153: 3319-3325, 1994). Alternatively antibodies, such asmonoclonal antibodies (MAb) to zcytor17-comprising receptors, can alsobe used as an antagonist to deplete unwanted immune cells to treatautoimmune disease. Asthma, allergy and other atopic disease may betreated with an MAb against, for example, soluble zcytor17 solublereceptors or zcytor17/CRF2-4 heterodimers, to inhibit the immuneresponse or to deplete offending cells. Blocking or inhibiting signalingvia zcytor17, using the polypeptides and antibodies of the presentinvention, may also benefit diseases of the pancreas, kidney, pituitaryand neuronal cells. IDDM, NIDDM, pancreatitis, and pancreatic carcinomamay benefit. Zcytor17 may serve as a target for MAb therapy of cancerwhere an antagonizing MAb inhibits cancer growth and targetsimmune-mediated killing. (Holliger P, and Hoogenboom, H: Nature Biotech.16: 1015-1016, 1998). Mabs to soluble zcytor17 monomers, homodimers,heterodimers and multimers may also be useful to treat nephropathiessuch as glomerulosclerosis, membranous neuropathy, amyloidosis (whichalso affects the kidney among other tissues), renal arteriosclerosis,glomerulonephritis of various origins, fibroproliferative diseases ofthe kidney, as well as kidney dysfunction associated with SLE, IDDM,type II diabetes (NIDDM), renal tumors and other diseases.

3) Agonize or initiate signaling via the zcytor17 receptors in thetreatment of autoimmune diseases such as IDDM, MS, SLE, myastheniagravis, rheumatoid arthritis, and IBD. Anti-zcytor17, anti-heterodimerand multimer monoclonal antibodies may signal lymphocytes or otherimmune cells to differentiate, alter proliferation, or change productionof cytokines or cell surface proteins that ameliorate autoimmunity.Specifically, modulation of a T-helper cell response to an alternatepattern of cytokine secretion may deviate an autoimmune response toameliorate disease (Smith J A et al., J. Immunol. 160:4841-4849, 1998).Similarly, agonistic anti- zcytor17, anti-heterodimer and multimermonoclonal antibodies may be used to signal, deplete and deviate immunecells involved in asthma, allergy and atopoic disease. Signaling viazcytor17 may also benefit diseases of the pancreas, kidney, pituitaryand neuronal cells. IDDM, NIDDM, pancreatitis, and pancreatic carcinomamay benefit. Zcytor17 may serve as a target for MAb therapy ofpancreatic cancer where a signaling MAb inhibits cancer growth andtargets immune-mediated killing (Tutt, AL et al., J Immunol. 161:3175-3185, 1998). Similarly T-cell specific leukemias, lymphomas, andcarcinoma may be treated with monoclonal antibodies tozcytor17-comprising soluble receptors of the present invention.

Soluble zcytor17 monomeric, homodimeric, heterodimeric and multimericpolypeptides described herein can be used to neutralize/block zcytor17ligand activity in the treatment of autoimmune disease, atopic disease,NIDDM, pancreatitis and kidney dysfunction as described above. A solubleform of zcytor17 may be used to promote an antibody response mediated byT cells and/or to promote the production of IL-4 or other cytokines bylymphocytes or other immune cells.

The soluble zcytor17-comprising receptors of the present invention areuseful as antagonists of its natural ligand. Such antagonistic effectscan be achieved by direct neutralization or binding of its naturalligand. In addition to antagonistic uses, the soluble receptors of thepresent invention can bind zcytor17 ligand and act as carrier proteinsfor the ligand, in order to transport the ligand to different tissues,organs, and cells within the body. As such, the soluble receptors of thepresent invention can be fused or coupled to molecules, polypeptides orchemical moieties that direct the soluble-receptor-Ligand complex to aspecific site, such as a tissue, specific immune cell, monocytes, ortumor. For example, in acute infection or some cancers, benefit mayresult from induction of inflammation and local acute phase responseproteins. Thus, the soluble receptors of the present invention can beused to specifically direct the action of a pro-inflammatory ligand.See, Cosman, D. Cytokine 5: 95-106, 1993; and Fernandez-Botran, R. Exp.Opin. Invest. Drugs 9:497-513, 2000.

Moreover, the soluble receptors of the present invention can be used tostabilize the zcytor17 ligand, to increase the bioavailability,therapeutic longevity, and/or efficacy of the Ligand by stabilizing theLigand from degradation or clearance, or by targeting the ligand to asite of action within the body. For example the naturally occurringIL-6/soluble IL-6R complex stabilizes IL-6 and can signal through thegp130 receptor. See, Cosman, D. supra., and Fernandez-Botran, R. supra.Moreover, Zcytor17 may be combined with a cognate ligand such as itsligand to comprise a ligand/soluble receptor complex. Such complexes maybe used to stimulate responses from cells presenting a companionreceptor subunit. The cell specificity of zcytor17/ligand complexes maydiffer from that seen for the ligand administered alone. Furthermore thecomplexes may have distinct pharmacokinetic properties such as affectinghalf-life, dose/response and organ or tissue specificity.Zcytor17/ligand complexes thus may have agonist activity to enhance animmune response or stimulate mesangial cells or to stimulate hepaticcells. Alternatively only tissues expressing a signaling subunit theheterodimerizes with the complex may be affected analogous to theresponse to IL6/IL6R complexes (Hirota H. et al., Proc. Nat'l. Acad.Sci. 92:4862-4866, 1995; Hirano, T. in Thomason, A. (Ed.) “The CytokineHandbook”, ₃ ^(rd) Ed., p. 208-209). Soluble receptor/cytokine complexesfor IL12 and CNTF display similar activities.

Zcytor17 homodimeric, heterodimeric and multimeric receptor polypeptidesmay also be used within diagnostic systems for the detection ofcirculating levels of ligand, and in the detection of acute phaseinflammatory response. Within a related embodiment, antibodies or otheragents that specifically bind to Zcytor17 soluble receptors of thepresent invention can be used to detect circulating receptorpolypeptides; conversely, Zcytor17 soluble receptors themselves can beused to detect circulating or locally-acting ligand polypeptides.Elevated or depressed levels of ligand or receptor polypeptides may beindicative of pathological conditions, including inflammation or cancer.Moreover, detection of acute phase proteins or molecules such aszcytor17 ligand can be indicative of a chronic inflammatory condition incertain disease states (e.g., rheumatoid arthritis). Detection of suchconditions serves to aid in disease diagnosis as well as help aphysician in choosing proper therapy.

Differentiation is a progressive and dynamic process, beginning withpluripotent stem cells and ending with terminally differentiated cells.Pluripotent stem cells that can regenerate without commitment to alineage express a set of differentiation markers that are lost whencommitment to a cell lineage is made. Progenitor cells express a set ofdifferentiation markers that may or may not continue to be expressed asthe cells progress down the cell lineage pathway toward maturation.Differentiation markers that are expressed exclusively by mature cellsare usually functional properties such as cell products, enzymes toproduce cell products, and receptors. The stage of a cell population'sdifferentiation is monitored by identification of markers present in thecell population. Myocytes, osteoblasts, adipocytes, chrondrocytes,fibroblasts and reticular cells are believed to originate from a commonmesenchymal stem cell (Owen et al., Ciba Fdn. Symp. 136:42-46, 1988).Markers for mesenchymal stem cells have not been well identified (Owenet al., J. of Cell Sci. 87:731-738, 1987), so identification is usuallymade at the progenitor and mature cell stages. The novel polypeptides ofthe present invention may be useful for studies to isolate mesenchymalstem cells and myocyte or other progenitor cells, both in vivo and exvivo.

There is evidence to suggest that factors that stimulate or regulatespecific cell types down a pathway towards terminal differentiation ordedifferentiation affect the entire cell population originating from acommon precursor or stem cell. Thus, the present invention includesstimulating or inhibiting the proliferation of lymphoid cells,hematopoietic cells and endothelial cells. Thus molecules of the presentinvention, such as soluble zcytor17 receptors, cytokine-bindingfragments, anti-zcytor17 antibodies, sense and antisense polynucleotidesmay have use in inhibiting tumor cells, and particularly lymphoid,hematopoietic, prostate, endothelial, and thyroid tumor cells.

Assays measuring differentiation include, for example, measuring cellmarkers associated with stage-specific expression of a tissue, enzymaticactivity, functional activity or morphological changes (Watt, FASEB,5:281-284, 1991; Francis, Differentiation 57:63-75, 1994; Raes, Adv.Anim. Cell Biol. Technol. Bioprocesses, 161-171, 1989; all incorporatedherein by reference). Alternatively, zcytor17 polypeptide itself canserve as an additional cell-surface or secreted marker associated withstage-specific expression of a tissue. As such, direct measurement ofzcytor17 polypeptide, or its loss of expression in a tissue as itdifferentiates, can serve as a marker for identification ordifferentiation of, e.g., prostate tissue, or monocyte cells.

Similarly, direct measurement of zcytor17 polypeptide, or its loss ofexpression in a tissue can be determined in a tissue or cells as theyundergo tumor progression. Increases in invasiveness and motility ofcells, or the gain or loss of expression of zcytor17 in a pre-cancerousor cancerous condition, in comparison to normal tissue, can serve as adiagnostic for transformation, invasion and metastasis in tumorprogression. As such, knowledge of a tumor's stage of progression ormetastasis will aid the physician in choosing the most proper therapy,or aggressiveness of treatment, for a given individual cancer patient.Methods of measuring gain and loss of expression (of either mRNA orprotein) are well known in the art and described herein and can beapplied to zcytor17 expression. For example, appearance or disappearanceof polypeptides that regulate cell motility can be used to aid diagnosisand prognosis of prostate cancer (Banyard, J. and Zetter, B. R., Cancerand Metast. Rev. 17:449-458, 1999). As an effector of cell motility,activation, proliferation, or differentiation, zcytor17 gain or loss ofexpression may serve as a diagnostic for lymphoid, hematopoietic,prostate, endothelial, and thyroid and other cancers.

In addition, as zcytor17 is monocyte and prostate-specific,polynucleotide probes, anti-zcytor17 antibodies, and detection thepresence of zcytor17 polypeptides in tissues can be used to assesswhether monocytes or prostate tissue is present, for example, aftersurgery involving the excision of a diseased or cancerous prostate, orin evaluation of monocyte infiltration in diseased or infected tissuesor monocyte cancers. As such, the polynucleotides, polypeptides, andantibodies of the present invention can be used as an aid to determinewhether all prostate tissue is excised after surgery, for example, aftersurgery for prostate cancer. In such instances, it is especiallyimportant to remove all potentially diseased tissue to maximize recoveryfrom the cancer, and to minimize recurrence. Moreover, thepolynucleotides, polypeptides, and antibodies of the present inventioncan be used as an aid to determine whether monocyte infiltration ispresent in diseased tissues (e.g., inflamed or infected) to monitor therecovery from disease or cancers. Preferred embodiments includefluorescent, radiolabeled, or calorimetrically labeled anti-zcytor17antibodies and zcytor17 polypeptide binding partners, that can be usedhistologically or in situ.

Moreover, the activity and effect of zcytor17 on tumor progression andmetastasis can be measured in vivo. Several syngeneic mouse models havebeen developed to study the influence of polypeptides, compounds orother treatments on tumor progression. In these models, tumor cellspassaged in culture are implanted into mice of the same strain as thetumor donor. The cells will develop into tumors having similarcharacteristics in the recipient mice, and metastasis will also occur insome of the models. Appropriate tumor models for our studies include theLewis lung carcinoma (ATCC No. CRL-1642) and B16 melanoma (ATCC No.CRL-6323), amongst others. These are both commonly used tumor lines,syngeneic to the C57BL6 mouse, that are readily cultured and manipulatedin vitro. Tumors resulting from implantation of either of these celllines are capable of metastasis to the lung in C57BL6 mice. The Lewislung carcinoma model has recently been used in mice to identify aninhibitor of angiogenesis (O'Reilly M S, et al. Cell 79: 315-328,1994).C57BL6/J mice are treated with an experimental agent either throughdaily injection of recombinant protein, agonist or antagonist or a onetime injection of recombinant adenovirus. Three days following thistreatment, 10⁵ to 10⁶ cells are implanted under the dorsal skin.Alternatively, the cells themselves may be infected with recombinantadenovirus, such as one expressing zcytor17, before implantation so thatthe protein is synthesized at the tumor site or intracellularly, ratherthan systemically. The mice normally develop visible tumors within 5days. The tumors are allowed to grow for a period of up to 3 weeks,during which time they may reach a size of 1500-1800 mm³ in the controltreated group. Tumor size and body weight are carefully monitoredthroughout the experiment. At the time of sacrifice, the tumor isremoved and weighed along with the lungs and the liver. The lung weighthas been shown to correlate well with metastatic tumor burden. As anadditional measure, lung surface metastases are counted. The resectedtumor, lungs and liver are prepared for histopathological examination,immunohistochemistry, and in situ hybridization, using methods known inthe art and described herein. The influence of the expressed polypeptidein question, e.g., zcytor17, on the ability of the tumor to recruitvasculature and undergo metastasis can thus be assessed. In addition,aside from using adenovirus, the implanted cells can be transientlytransfected with zcytor17. Use of stable zcytor17 transfectants as wellas use of induceable promoters to activate zcytor17 expression in vivoare known in the art and can be used in this system to assess zcytor17induction of metastasis. Moreover, purified zcytor17 or zcytor17conditioned media can be directly injected in to this mouse model, andhence be used in this system. For general reference see, O'Reilly M S,et al. Cell 79:315-328, 1994; and Rusciano D, et al. Murine Models ofLiver Metastasis. Invasion Metastasis 14:349-361, 1995.

The activity of zcytor17 and its derivatives (conjugates) on growth anddissemination of tumor cells derived from human hematologic malignanciescan also be measured in vivo in a mouse Xenograft model Several mousemodels have been developed in which human tumor cells are implanted intoimmunodeficient mice, collectively referred to as xenograft models. SeeCattan, A R and Douglas, E Leuk. Res. 18:513-22, 1994; and Flavell, D J,Hematological Oncology 14:67-82, 1996. The characteristics of thedisease model vary with the type and quantity of cells delivered to themouse. Typically, the tumor cells will proliferate rapidly and can befound circulating in the blood and populating numerous organ systems.Therapeutic strategies appropriate for testing in such a model includeantibody induced toxicity, ligand-toxin conjugates or cell-basedtherapies. The latter method, commonly referred to adoptiveimmunotherapy, involves treatment of the animal with components of thehuman immune system (i.e. lymphocytes, NK cells) and may include ex vivoincubation of cells with zcytor17 or other immunomodulatory agents.

The mRNA corresponding to this novel DNA showed expression in lymphoidtissues, including thymus, is expressed in bone marrow and prostate,monocytes, and activated monocytes, CD19+ B-cells, and may be expressedin spleen, lymph nodes, and peripheral blood leukocytes. These dataindicate a role for the zcytor17 receptor in proliferation,differentiation, and/or activation of immune cells, and suggest a rolein development and regulation of immune responses. The data also suggestthat the interaction of zcytor17 with its ligand may stimulateproliferation and development of myeloid cells and may, like IL-2, IL-6,LIF, IL-11, IL-12 and OSM (Baumann et al., J. Biol. Chem. 268:8414-8417,1993), induce acute-phase protein synthesis in hepatocytes.

It is preferred to purify the polypeptides of the present invention to≧80% purity, more preferably to ≧90% purity, even more preferably ≧95%purity, and particularly preferred is a pharmaceutically pure state,that is greater than 99.9% pure with respect to contaminatingmacromolecules, particularly other proteins and nucleic acids, and freeof infectious and pyrogenic agents. Preferably, a purified polypeptideis substantially free of other polypeptides, particularly otherpolypeptides of animal origin.

Expressed recombinant zcytor17 polypeptides (or zcytor17 chimeric orfusion polypeptides) can be purified using fractionation and/orconventional purification methods and media. Ammonium sulfateprecipitation and acid or chaotrope extraction may be used forfractionation of samples. Exemplary purification steps may includehydroxyapatite, size exclusion, FPLC and reverse-phase high performanceliquid chromatography. Suitable chromatographic media includederivatized dextrans, agarose, cellulose, polyacrylamide, specialtysilicas, and the like. PEI, DEAE, QAE and Q derivatives are preferred.Exemplary chromatographic media include those media derivatized withphenyl, butyl, or octyl groups, such as Phenyl-Sepharose FF (Pharmacia),Toyopearl butyl 650 (Toso Haas, Montgomeryville, Pa.), Octyl-Sepharose(Pharmacia) and the like; or polyacrylic resins, such as Amberchrom CG71 (Toso Haas) and the like. Suitable solid supports include glassbeads, silica-based resins, cellulosic resins, agarose beads,cross-linked agarose beads, polystyrene beads, cross-linkedpolyacrylamide resins and the like that are insoluble under theconditions in which they are to be used. These supports may be modifiedwith reactive groups that allow attachment of proteins by amino groups,carboxyl groups, sulfhydryl groups, hydroxyl groups and/or carbohydratemoieties. Examples of coupling chemistries include cyanogen bromideactivation, N-hydroxysuccinimide activation, epoxide activation,sulfhydryl activation, hydrazide activation, and carboxyl and aminoderivatives for carbodiimide coupling chemistries. These and other solidmedia are well known and widely used in the art, and are available fromcommercial suppliers. Methods for binding receptor polypeptides tosupport media are well known in the art. Selection of a particularmethod is a matter of routine design and is determined in part by theproperties of the chosen support. See, for example, AffinityChromatography: Principles & Methods, Pharmacia LKB Biotechnology,Uppsala, Sweden, 1988.

The polypeptides of the present invention can be isolated byexploitation of their biochemical, structural, and biologicalproperties. For example, immobilized metal ion adsorption (IMAC)chromatography can be used to purify histidine-rich proteins, includingthose comprising polyhistidine tags. Briefly, a gel is first chargedwith divalent metal ions to form a chelate (Sulkowski, Trends inBiochem. 3:1-7, 1985). Histidine-rich proteins will be adsorbed to thismatrix with differing affinities, depending upon the metal ion used, andwill be eluted by competitive elution, lowering the pH, or use of strongchelating agents. Other methods of purification include purification ofglycosylated proteins by lectin affinity chromatography and ion exchangechromatography (Methods in Enzymol., Vol. 182, “Guide to ProteinPurification”, M. Deutscher, (ed.), Acad. Press, San Diego, 1990,pp.529-39). Within additional embodiments of the invention, a fusion ofthe polypeptide of interest and an affinity tag (e.g., maltose-bindingprotein, an immunoglobulin domain) may be constructed to facilitatepurification.

Moreover, using methods described in the art, polypeptide fusions, orhybrid zcytor17 proteins, are constructed using regions or domains ofthe inventive zcytor17 in combination with those of other human cytokinereceptor family proteins, or heterologous proteins (Sambrook et al.,ibid., Altschul et al., ibid., Picard, Cur. Opin. Biology, 5:511-5,1994, and references therein). These methods allow the determination ofthe biological importance of larger domains or regions in a polypeptideof interest. Such hybrids may alter reaction kinetics, binding,constrict or expand the substrate specificity, or alter tissue andcellular localization of a polypeptide, and can be applied topolypeptides of unknown structure.

Fusion polypeptides or proteins can be prepared by methods known tothose skilled in the art by preparing each component of the fusionprotein and chemically conjugating them. Alternatively, a polynucleotideencoding one or more components of the fusion protein in the properreading frame can be generated using known techniques and expressed bythe methods described herein. For example, part or all of a domain(s)conferring a biological function may be swapped between zcytor17 of thepresent invention with the functionally equivalent domain(s) fromanother cytokine family member. Such domains include, but are notlimited to, the secretory signal sequence, extracellular domain,cytokine binding domain, fibronectin type III domain, transmembranedomain, and intracellular signaling domain, Box I and Box II sites, asdisclosed herein. Such fusion proteins would be expected to have abiological functional profile that is the same or similar topolypeptides of the present invention or other known family proteins,depending on the fusion constructed. Moreover, such fusion proteins mayexhibit other properties as disclosed herein.

Standard molecular biological and cloning techniques can be used to swapthe equivalent domains between the zcytor17 polypeptide and thosepolypeptides to which they are fused. Generally, a DNA segment thatencodes a domain of interest, e.g., a zcytor17 domain described herein,is operably linked in frame to at least one other DNA segment encodingan additional polypeptide (for instance a domain or region from anothercytokine receptor, such as the gp130, LIF, IL-12, WSX-1, IL-2 or otherclass I cytokine receptor), and inserted into an appropriate expressionvector, as described herein. Generally DNA constructs are made such thatthe several DNA segments that encode the corresponding regions of apolypeptide are operably linked in frame to make a single construct thatencodes the entire fusion protein, or a functional portion thereof. Forexample, a DNA construct would encode from N-terminus to C-terminus afusion protein comprising a signal polypeptide followed by a cytokinebinding domain, followed by a transmembrane domain, followed by anintracellular signaling domain. Such fusion proteins can be expressed,isolated, and assayed for activity as described herein. Moreover, suchfusion proteins can be used to express and secrete fragments of thezcytor17 polypeptide, to be used, for example to inoculate an animal togenerate anti-zcytor17 antibodies as described herein. For example asecretory signal sequence can be operably linked to the cytokine bindingdomain, transmembrane domain, intracellular signaling domain orsubfragment thereof, or a combination thereof (e.g., operably linkedpolypeptides comprising the extracellular cytokine binding domain fusedto a transmembrane domain, or zcytor17 polypeptide fragments describedherein), to secrete a fragment of zcytor17 polypeptide that can bepurified as described herein and serve as an antigen to be inoculatedinto an animal to produce anti-zcytor17 antibodies, as described herein.

Zcytor17 polypeptides or fragments thereof may also be prepared throughchemical synthesis. zcytor17 polypeptides may be monomers or multimers;glycosylated or non-glycosylated; pegylated or non-pegylated; and may ormay not include an initial methionine amino acid residue.

Polypeptides of the present invention can also be synthesized byexclusive solid phase synthesis, partial solid phase methods, fragmentcondensation or classical solution synthesis. Methods for synthesizingpolypeptides are well known in the art. See, for example, Merrifield, J.Am. Chem. Soc. 85:2149, 1963; Kaiser et al., Anal. Biochem. 34:595,1970. After the entire synthesis of the desired peptide on a solidsupport, the peptide-resin is with a reagent which cleaves thepolypeptide from the resin and removes most of the side-chain protectinggroups. Such methods are well established in the art.

The activity of molecules of the present invention can be measured usinga variety of assays that measure cell differentiation and proliferation.Such assays are well known in the art.

Proteins of the present invention are useful for example, in treatingand diagnosing lymphoid, immune, inflammatory, spleenic, blood or bonedisorders, and can be measured in vitro using cultured cells or in vivoby administering molecules of the present invention to the appropriateanimal model. For instance, host cells expressing a zcytor17 solublereceptor polypeptide can be embedded in an alginate environment andinjected (implanted) into recipient animals. Alginate-poly-L-lysinemicroencapsulation, permselective membrane encapsulation and diffusionchambers are a means to entrap transfected mammalian cells or primarymammalian cells. These types of non-immunogenic “encapsulations” permitthe diffusion of proteins and other macromolecules secreted or releasedby the captured cells to the recipient animal. Most importantly, thecapsules mask and shield the foreign, embedded cells from the recipientanimal's immune response. Such encapsulations can extend the life of theinjected cells from a few hours or days (naked cells) to several weeks(embedded cells). Alginate threads provide a simple and quick means forgenerating embedded cells.

The materials needed to generate the alginate threads are known in theart. In an exemplary procedure, 3% alginate is prepared in sterile H₂O,and sterile filtered. Just prior to preparation of alginate threads, thealginate solution is again filtered. An approximately 50% cellsuspension (containing about 5×10⁵ to about 5×10⁷ cells/ml) is mixedwith the 3% alginate solution. One ml of the alginate/cell suspension isextruded into a 100 mM sterile filtered CaCl₂ solution over a timeperiod of ˜15 min, forming a “thread”. The extruded thread is thentransferred into a solution of 50 mM CaCl₂, and then into a solution of25 mM CaCl₂. The thread is then rinsed with deionized water beforecoating the thread by incubating in a 0.01% solution of poly-L-lysine.Finally, the thread is rinsed with Lactated Ringer's Solution and drawnfrom solution into a syringe barrel (without needle). A large boreneedle is then attached to the syringe, and the thread isintraperitoneally injected into a recipient in a minimal volume of theLactated Ringer's Solution.

An in vivo approach for assaying proteins of the present inventioninvolves viral delivery systems. Exemplary viruses for this purposeinclude adenovirus, herpesvirus, retroviruses, vaccinia virus, andadeno-associated virus (AAV). Adenovirus, a double-stranded DNA virus,is currently the best studied gene transfer vector for delivery ofheterologous nucleic acid (for review, see T. C. Becker et al., Meth.Cell Biol. 43:161-89, 1994; and J. T. Douglas and D. T. Curiel, Science& Medicine 4:44-53, 1997). The adenovirus system offers severaladvantages: (i) adenovirus can accommodate relatively large DNA inserts;(ii) can be grown to high-titer; (iii) infect a broad range of mammaliancell types; and (iv) can be used with a large number of differentpromoters including ubiquitous, tissue specific, and regulatablepromoters. Also, because adenoviruses are stable in the bloodstream,they can be administered by intravenous injection.

Using adenovirus vectors where portions of the adenovirus genome aredeleted, inserts are incorporated into the viral DNA by direct ligationor by homologous recombination with a co-transfected plasmid. In anexemplary system, the essential E1 gene has been deleted from the viralvector, and the virus will not replicate unless the E1 gene is providedby the host cell (the human 293 cell line is exemplary). Whenintravenously administered to intact animals, adenovirus primarilytargets the liver. If the adenoviral delivery system has an E1 genedeletion, the virus cannot replicate in the host cells. However, thehost's tissue (e.g., liver) will express and process (and, if asecretory signal sequence is present, secrete) the heterologous protein.Secreted proteins will enter the circulation in the highly vascularizedliver, and effects on the infected animal; can be determined.

Moreover, adenoviral vectors containing various deletions of viral genescan be used in an attempt to reduce or eliminate immune responses to thevector. Such adenoviruses are E1 deleted, and in addition containdeletions of E2A or E4 (Lusky, M. et al., J. Virol. 72:2022-2032, 1998;Raper, S. E. et al., Human Gene Therapy 9:671-679, 1998). In addition,deletion of E2b is reported to reduce immune responses (Amalfitano, A.et al., J. Virol. 72:926-933, 1998). Moreover, by deleting the entireadenovirus genome, very large inserts of heterologous DNA can beaccommodated. Generation of so called “gutless” adenoviruses where allviral genes are deleted are particularly advantageous for insertion oflarge inserts of heterologous DNA. For review, see Yeh, P. andPerricaudet, M., FASEB J. 11:615-623, 1997.

The adenovirus system can also be used for protein production in vitro.By culturing adenovirus-infected non-293 cells under conditions wherethe cells are not rapidly dividing, the cells can produce proteins forextended periods of time. For instance, BHK cells are grown toconfluence in cell factories, then exposed to the adenoviral vectorencoding the secreted protein of interest. The cells are then grownunder serum-free conditions, which allows infected cells to survive forseveral weeks without significant cell division. Alternatively,adenovirus vector infected 293 cells can be grown as adherent cells orin suspension culture at relatively high cell density to producesignificant amounts of protein (See Garnier et al., Cytotechnol.15:145-55, 1994). With either protocol, an expressed, secretedheterologous protein can be repeatedly isolated from the cell culturesupernatant, lysate, or membrane fractions depending on the dispositionof the expressed protein in the cell. Within the infected 293 cellproduction protocol, non-secreted proteins may also be effectivelyobtained.

In view of the tissue distribution observed for zcytor17, agonists(including the natural ligand/ substrate/ cofactor/ etc.) andantagonists have enormous potential in both in vitro and in vivoapplications. Compounds identified as zcytor17 agonists are useful forstimulating growth of immune and hematopoietic cells in vitro and invivo. For example, zcytor17 soluble receptors, and agonist compounds areuseful as components of defined cell culture media, and may be usedalone or in combination with other cytokines and hormones to replaceserum that is commonly used in cell culture. Agonists are thus useful inspecifically promoting the growth and/or development of T-cells,B-cells, and other cells of the lymphoid and myeloid lineages inculture. Moreover, zcytor17 soluble receptor, agonist, or antagonist maybe used in vitro in an assay to measure stimulation of colony formationfrom isolated primary bone marrow cultures. Such assays are well knownin the art.

Antagonists are also useful as research reagents for characterizingsites of ligand-receptor interaction. Inhibitors of zcytor17 activity(zcytor17 antagonists) include anti-zcytor17 antibodies and solublezcytor17 receptors, as well as other peptidic and non-peptidic agents(including ribozymes).

Zcytor17 can also be used to identify modulators (e.g, antagonists) ofits activity. Test compounds are added to the assays disclosed herein toidentify compounds that inhibit the activity of zcytor17. In addition tothose assays disclosed herein, samples can be tested for inhibition ofzcytor17 activity within a variety of assays designed to measurezcytor17 binding, oligomerization, or the stimulation/inhibition ofzcytor17-dependent cellular responses. For example, zcytor17-expressingcell lines can be transfected with a reporter gene construct that isresponsive to a zcytor17-stimulated cellular pathway. Reporter geneconstructs of this type are known in the art, and will generallycomprise a zcytor17-DNA response element operably linked to a geneencoding an assay detectable protein, such as luciferase. DNA responseelements can include, but are not limited to, cyclic AMP responseelements (CRE), hormone response elements (HRE) insulin response element(IRE) (Nasrin et al., Proc. Natl. Acad. Sci. USA 87:5273-7, 1990) andserum response elements (SRE) (Shaw et al. Cell 56: 563-72, 1989).Cyclic AMP response elements are reviewed in Roestler et al., J. Biol.Chem. 263 (19):9063-6; 1988 and Habener, Molec. Endocrinol. 4(8):1087-94; 1990. Hormone response elements are reviewed in Beato, Cell56:335-44; 1989. Candidate compounds, solutions, mixtures or extracts orconditioned media from various cell types are tested for the ability toenhance the activity of zcytor17 receptor as evidenced by a increase inzcytor17 stimulation of reporter gene expression. Assays of this typewill detect compounds that directly stimulate zcytor17 signaltransduction activity through binding the receptor or by otherwisestimulating part of the signal cascade. As such, there is provided amethod of identifying agonists of zcytor17 polypeptide, comprisingproviding cells responsive to a zcytor17 polypeptide, culturing a firstportion of the cells in the absence of a test compound, culturing asecond portion of the cells in the presence of a test compound, anddetecting a increase in a cellular response of the second portion of thecells as compared to the first portion of the cells. Moreover thirdcell, containing the reporter gene construct described above, but notexpressing zcytor17 receptor, can be used as a control cell to assessnon-specific, or non-zcytor17-mediated, stimulation of the reporter.Agonists, including the natural ligand, are therefore useful tostimulate or increase zcytor17 polypeptide function.

A zcytor17 ligand-binding polypeptide, such as the extracellular domainor cytokine binding domain disclosed herein, can also be used forpurification of ligand. The polypeptide is immobilized on a solidsupport, such as beads of agarose, cross-linked agarose, glass,cellulosic resins, silica-based resins, polystyrene, cross-linkedpolyacrylamide, or like materials that are stable under the conditionsof use. Methods for linking polypeptides to solid supports are known inthe art, and include amine chemistry, cyanogen bromide activation,N-hydroxysuccinimide activation, epoxide activation, sulfhydrylactivation, and hydrazide activation. The resulting medium willgenerally be configured in the form of a column, and fluids containingligand are passed through the column one or more times to allow ligandto bind to the receptor polypeptide. The ligand is then eluted usingchanges in salt concentration, chaotropic agents (guanidine HCl), or pHto disrupt ligand-receptor binding.

An assay system that uses a ligand-binding receptor (or an antibody, onemember of a complement/ anti-complement pair) or a binding fragmentthereof, and a commercially available biosensor instrument may beadvantageously employed (e.g., BIAcore ™, Pharmacia Biosensor,Piscataway, N.J.; or SELDI™ technology, Ciphergen, Inc., Palo Alto,Calif.). Such receptor, antibody, member of a complement/anti-complementpair or fragment is immobilized onto the surface of a receptor chip. Useof this instrument is disclosed by Karlsson, J. Immunol. Methods145:229-240, 1991 and Cunningham and Wells, J. Mol. Biol. 234:554-63,1993. A receptor, antibody, member or fragment is covalently attached,using amine or sulfhydryl chemistry, to dextran fibers that are attachedto gold film within the flow cell. A test sample is passed through thecell. If a ligand, epitope, or opposite member of thecomplement/anti-complement pair is present in the sample, it will bindto the immobilized receptor, antibody or member, respectively, causing achange in the refractive index of the medium, which is detected as achange in surface plasmon resonance of the gold film. This system allowsthe determination of on- and off-rates, from which binding affinity canbe calculated, and assessment of stoichiometry of binding.

Ligand-binding receptor polypeptides can also be used within other assaysystems known in the art. Such systems include Scatchard analysis fordetermination of binding affinity (see Scatchard, Ann. NY Acad. Sci. 51:660-672, 1949) and calorimetric assays (Cunningham et al., Science253:545-48, 1991; Cunningham et al., Science 245:821-25, 1991).

Zcytor17 polypeptides can also be used to prepare antibodies that bindto zcytor17 epitopes, peptides or polypeptides. The zcytor17 polypeptideor a fragment thereof serves as an antigen (immunogen) to inoculate ananimal and elicit an immune response. One of skill in the art wouldrecognize that antigenic, epitope-bearing polypeptides contain asequence of at least 6, preferably at least 9, and more preferably atleast 15 to about 30 contiguous amino acid residues of a zcytor17polypeptide (e.g., SEQ ID NO:54, SEQ IDNO:57, and the like).Polypeptides comprising a larger portion of a zcytor17 polypeptide,i.e., from 30 to 100 residues up to the entire length of the amino acidsequence are included. Antigens or immunogenic epitopes can also includeattached tags, adjuvants and carriers, as described herein. Suitableantigens include the zcytor17 polypeptide encoded by SEQ ID NO:2 fromamino acid number 20 (Ala) to amino acid number 732 (Val), or acontiguous 9 to 713, or 30 or 50 to 713 amino acid fragment thereof; andSEQ ID NO:46 from amino acid number 20 (Ala) to amino acid number 649(Ile), or a contiguous 9 to 630, or 30 or 50 to 630 amino acid fragmentthereof; and SEQ ID NO:54 from amino acid number 33 (Ala) to amino acidnumber 662 (Ile), or a contiguous 9 to 630, or 30 or 50 to 630 aminoacid fragment thereof. Preferred peptides to use as antigens are theextracellular domain, cytokine binding domain, fibronectin type IIIdomain, intracellular signaling domain, Box I and Box II sites or otherdomains and motifs disclosed herein, or a combination thereof; andzcytor17 hydrophilic peptides such as those predicted by one of skill inthe art from a hydrophobicity plot, determined for example, from aHopp/Woods hydrophilicity profile based on a sliding six-residue window,with buried G, S, and T residues and exposed H, Y, and W residuesignored. Zcytor17 hydrophilic peptides include peptides comprising aminoacid sequences selected from the group consisting of: (1) amino acidresidues 43 through 48 of SEQ ID NO:2 and SEQ ID NO:46 (residues 56through 61 of SEQ ID NO:54); (2) amino acid residues 157 through 162 ofSEQ ID NO:2 and SEQ ID NO:46 (residues 170 through 175 of SEQ ID NO:54);(3) amino acid residues 158 through 163 of SEQ ID NO:2 and SEQ ID NO:46(171 through 176 of SEQ ID NO:54); (4) amino acid residues 221 through226 of SEQ ID NO:2 and SEQ ID NO:46 (234 through 239 of SEQ ID NO:54);and (5) amino acid residues 426 through 431 of SEQ ID NO:2 and SEQ IDNO:46 (residues 439 through 444 of SEQ ID NO:54). In addition,hydrophilic epitopes predicted from a Jameson-Wolf plot Jameson-Wolfplot, e.g., using DNASTAR Protean program (DNASTAR, Inc., Madison, WI),are also suitable antigens. In addition, conserved motifs, and variableregions between conserved motifs of zcytor17 are suitable antigens.Antibodies generated from this immune response can be isolated andpurified as described herein. Methods for preparing and isolatingpolyclonal and monoclonal antibodies are well known in the art. See, forexample, Current Protocols in Immunology, Cooligan, et al. (eds.),National Institutes of Health, John Wiley and Sons, Inc., 1995; Sambrooket al., Molecular Cloning: A Laboratory Manual, Second Edition, ColdSpring Harbor, N.Y., 1989; and Hurrell, J. G. R., Ed., MonoclonalHybridoma Antibodies: Techniques and Applications, CRC Press, Inc., BocaRaton, Fla., 1982.

As would be evident to one of ordinary skill in the art, polyclonalantibodies can be generated from inoculating a variety of warm-bloodedanimals such as horses, cows, goats, sheep, dogs, chickens, rabbits,mice, and rats with a zcytor17 polypeptide or a fragment thereof. Theimmunogenicity of a zcytor17 polypeptide may be increased through theuse of an adjuvant, such as alum (aluminum hydroxide) or Freund'scomplete or incomplete adjuvant. Polypeptides useful for immunizationalso include fusion polypeptides, such as fusions of zcytor17 or aportion thereof with an immunoglobulin polypeptide or with maltosebinding protein. The polypeptide immunogen may be a full-length moleculeor a portion thereof. If the polypeptide portion is “hapten-like”, suchportion may be advantageously joined or linked to a macromolecularcarrier (such as keyhole limpet hemocyanin (KLH), bovine serum albumin(BSA) or tetanus toxoid) for immunization.

As used herein, the term “antibodies” includes polyclonal antibodies,affinity-purified polyclonal antibodies, monoclonal antibodies, andantigen-binding fragments, such as F(ab′)₂ and Fab proteolyticfragments. Genetically engineered intact antibodies or fragments, suchas chimeric antibodies, Fv fragments, single chain antibodies and thelike, as well as synthetic antigen-binding peptides and polypeptides,are also included. Non-human antibodies may be humanized by graftingnon-human CDRs onto human framework and constant regions, or byincorporating the entire non-human variable domains (optionally“cloaking” them with a human-like surface by replacement of exposedresidues, wherein the result is a “veneered” antibody). In someinstances, humanized antibodies may retain non-human residues within thehuman variable region framework domains to enhance proper bindingcharacteristics. Through humanizing antibodies, biological half-life maybe increased, and the potential for adverse immune reactions uponadministration to humans is reduced. Moreover, human antibodies can beproduced in transgenic, non-human animals that have been engineered tocontain human immunoglobulin genes as disclosed in WIPO Publication WO98/24893. It is preferred that the endogenous immunoglobulin genes inthese animals be inactivated or eliminated, such as by homologousrecombination.

Alternative techniques for generating or selecting antibodies usefulherein include in vitro exposure of lymphocytes to zcytor17 protein orpeptide, and selection of antibody display libraries in phage or similarvectors (for instance, through use of immobilized or labeled zcytor17protein or peptide). Genes encoding polypeptides having potentialzcytor17 polypeptide binding domains can be obtained by screening randompeptide libraries displayed on phage (phage display) or on bacteria,such as E. coli. Nucleotide sequences encoding the polypeptides can beobtained in a number of ways, such as through random mutagenesis andrandom polynucleotide synthesis. These random peptide display librariescan be used to screen for peptides which interact with a known targetwhich can be a protein or polypeptide, such as a ligand or receptor, abiological or synthetic macromolecule, or organic or inorganicsubstances. Techniques for creating and screening such random peptidedisplay libraries are known in the art (Ladner et al., U.S. Pat. No.5,223,409; Ladner et al., U.S. Pat. No. 4,946,778; Ladner et al., U.S.Pat. No. 5,403,484 and Ladner et al., U.S. Pat. No. 5,571,698) andrandom peptide display libraries and kits for screening such librariesare available commercially, for instance from Clontech (Palo Alto,Calif.), Invitrogen Inc. (San Diego, Calif.), New England Biolabs, Inc.(Beverly, Mass.) and Pharmacia LKB Biotechnology Inc. (Piscataway,N.J.). Random peptide display libraries can be screened using thezcytor17 sequences disclosed herein to identify proteins which bind tozcytor17. These “binding peptides” which interact with zcytor17polypeptides can be used for tagging cells that express the receptor;for isolating homolog polypeptides by affinity purification; they can bedirectly or indirectly conjugated to drugs, toxins, radionuclides andthe like. These binding peptides can also be used in analytical methodssuch as for screening expression libraries and neutralizing activity.The binding peptides can also be used for diagnostic assays fordetermining circulating levels of zcytor17 polypeptides; for detectingor quantitating soluble zcytor17 polypeptides as marker of underlyingpathology or disease. These binding peptides can also act as zcytor17“antagonists” to block zcytor17 binding and signal transduction in vitroand in vivo. These anti-zcytor17 binding peptides would be useful forinhibiting the action of a ligand that binds with zcytor17.

Antibodies are considered to be specifically binding if: 1) they exhibita threshold level of binding activity, and 2) they do not significantlycross-react with related polypeptide molecules. A threshold level ofbinding is determined if anti-zcytor17 antibodies herein bind to azcytor17 polypeptide, peptide or epitope with an affinity at least10-fold greater than the binding affinity to control (non-zcytor17)polypeptide. It is preferred that the antibodies exhibit a bindingaffinity (K_(a)) of 10⁶ M⁻¹ or greater, preferably 10⁷ M⁻¹ or greater,more preferably 10⁸ M⁻¹ or greater, and most preferably 10⁹ M⁻¹ orgreater. The binding affinity of an antibody can be readily determinedby one of ordinary skill in the art, for example, by Scatchard analysis(Scatchard, G., Ann. NY Acad. Sci. 51: 660-672, 1949).

Whether anti-zcytor17 antibodies do not significantly cross-react withrelated polypeptide molecules is shown, for example, by the antibodydetecting zcytor17 polypeptide but not known related polypeptides usinga standard Western blot analysis (Ausubel et al., ibid.). Examples ofknown related polypeptides are those disclosed in the prior art, such asknown orthologs, and paralogs, and similar known members of a proteinfamily (e.g., gp130, LIF, WSX-1 and IL12 receptors). Screening can alsobe done using non-human zcytor17, and zcytor17 mutant polypeptides.Moreover, antibodies can be “screened against” known relatedpolypeptides, to isolate a population that specifically binds to thezcytor17 polypeptides. For example, antibodies raised to zcytor17 areadsorbed to related polypeptides adhered to insoluble matrix; antibodiesspecific to zcytor17 will flow through the matrix under the properbuffer conditions. Screening allows isolation of polyclonal andmonoclonal antibodies non-crossreactive to known closely relatedpolypeptides (Antibodies: A Laboratory Manual, Harlow and Lane (eds.),Cold Spring Harbor Laboratory Press, 1988; Current Protocols inImmunology, Cooligan, et al. (eds.), National Institutes of Health, JohnWiley and Sons, Inc., 1995). Screening and isolation of specificantibodies is well known in the art. See, Fundamental Immunology, Paul(eds.), Raven Press, 1993; Getzoff et al., Adv. in Immunol. 43: 1-98,1988; Monoclonal Antibodies: Principles and Practice, Goding, J. W.(eds.), Academic Press Ltd., 1996; Benjamin et al., Ann. Rev. Immunol.2: 67-101, 1984. Specifically binding anti-zcytor17 antibodies can bedetected by a number of methods in the art, and disclosed below.

A variety of assays known to those skilled in the art can be utilized todetect antibodies which specifically bind to zcytor17 proteins orpeptides. Exemplary assays are described in detail in Antibodies: ALaboratory Manual, Harlow and Lane (Eds.), Cold Spring Harbor LaboratoryPress, 1988. Representative examples of such assays include: concurrentimmunoelectrophoresis, radioimmunoassay, radioimmuno-precipitation,enzyme-linked immunosorbent assay (ELISA), dot blot or Western blotassay, inhibition or competition assay, and sandwich assay. In addition,antibodies can be screened for binding to wild-type versus mutantzcytor17 protein or polypeptide.

Antibodies to zcytor17 may be used for tagging cells that expresszcytor17, such as cells that naturally express zcytor17 such as monocyteand prostate cells, as well as cells that are transformed with zcytor17;for isolating zcytor17 by affinity purification; for diagnostic assaysfor determining circulating levels of zcytor17 polypeptides; fordetecting or quantitating soluble zcytor17 as marker of underlyingpathology or disease; in analytical methods employing FACS; forscreening expression libraries; for generating anti-idiotypicantibodies; and as neutralizing antibodies or as antagonists to blockzcytor17 activity in vitro and in vivo. Suitable direct tags or labelsinclude radionuclides, enzymes, substrates, cofactors, inhibitors,fluorescent markers, chemiluminescent markers, magnetic particles andthe like; indirect tags or labels may feature use of biotin-avidin orother complement/anti-complement pairs as intermediates. Antibodiesherein may also be directly or indirectly conjugated to drugs, toxins,radionuclides and the like, and these conjugates used for in vivodiagnostic or therapeutic applications. Moreover, antibodies to zcytor17or fragments thereof may be used in vitro to detect denatured zcytor17or fragments thereof in assays, for example, Western Blots or otherassays known in the art.

Antibodies to zcytor17 are useful for tagging cells that express thereceptor and assaying Zcytor17 expression levels, for affinitypurification, within diagnostic assays for determining circulatinglevels of soluble receptor polypeptides, analytical methods employingfluorescence-activated cell sorting. Divalent antibodies may be used asagonists to mimic the effect of a zcytor17 ligand.

Antibodies herein can also be directly or indirectly conjugated todrugs, toxins, radionuclides and the like, and these conjugates used forin vivo diagnostic or therapeutic applications. For instance, antibodiesor binding polypeptides which recognize zcytor17 of the presentinvention can be used to identify or treat tissues or organs thatexpress a corresponding anti-complementary molecule (i.e., a zcytor17receptor). More specifically, anti-zcytor17 antibodies, or bioactivefragments or portions thereof, can be coupled to detectable or cytotoxicmolecules and delivered to a mammal having cells, tissues or organs thatexpress the zcytor17 molecule.

Suitable detectable molecules may be directly or indirectly attached topolypeptides that bind zcytor17 (“binding polypeptides,” includingbinding peptides disclosed above), antibodies, or bioactive fragments orportions thereof. Suitable detectable molecules include radionuclides,enzymes, substrates, cofactors, inhibitors, fluorescent markers,chemiluminescent markers, magnetic particles and the like. Suitablecytotoxic molecules may be directly or indirectly attached to thepolypeptide or antibody, and include bacterial or plant toxins (forinstance, diphtheria toxin, Pseudomonas exotoxin, ricin, abrin and thelike), as well as therapeutic radionuclides, such as iodine-131,rhenium-188 or yttrium-90 (either directly attached to the polypeptideor antibody, or indirectly attached through means of a chelating moiety,for instance). Binding polypeptides or antibodies may also be conjugatedto cytotoxic drugs, such as adriamycin. For indirect attachment of adetectable or cytotoxic molecule, the detectable or cytotoxic moleculecan be conjugated with a member of a complementary/ anticomplementarypair, where the other member is bound to the binding polypeptide orantibody portion. For these purposes, biotin/streptavidin is anexemplary complementary/ anticomplementary pair.

In another embodiment, binding polypeptide-toxin fusion proteins orantibody-toxin fusion proteins can be used for targeted cell or tissueinhibition or ablation (for instance, to treat cancer cells or tissues).Alternatively, if the binding polypeptide has multiple functionaldomains (i.e., an activation domain or a ligand binding domain, plus atargeting domain), a fusion protein including only the targeting domainmay be suitable for directing a detectable molecule, a cytotoxicmolecule or a complementary molecule to a cell or tissue type ofinterest. In instances where the fusion protein including only a singledomain includes a complementary molecule, the anti-complementarymolecule can be conjugated to a detectable or cytotoxic molecule. Suchdomain-complementary molecule fusion proteins thus represent a generictargeting vehicle for cell/tissue-specific delivery of genericanti-complementary-detectable/ cytotoxic molecule conjugates.

In another embodiment, zcytor17 binding polypeptide-cytokine orantibody-cytokine fusion proteins can be used for enhancing in vivokilling of target tissues (for example, blood, lymphoid, colon, and bonemarrow cancers), if the binding polypeptide-cytokine or anti-zcytor17antibody targets the hyperproliferative cell (See, generally, Hornick etal., Blood 89:4437-47, 1997). They described fusion proteins enabletargeting of a cytokine to a desired site of action, thereby providingan elevated local concentration of cytokine. Suitable anti-zcytor17antibodies target an undesirable cell or tissue (i.e., a tumor or aleukemia), and the fused cytokine mediates improved target cell lysis byeffector cells. Suitable cytokines for this purpose include interleukin2 and granulocyte-macrophage colony-stimulating factor (GM-CSF), forinstance.

Alternatively, zcytor17 binding polypeptide or antibody fusion proteinsdescribed herein can be used for enhancing in vivo killing of targettissues by directly stimulating a zcytor17-modulated apoptotic pathway,resulting in cell death of hyperproliferative cells expressing zcytor17.

The bioactive binding polypeptide or antibody conjugates describedherein can be delivered orally, intravenously, intraarterially orintraductally, or may be introduced locally at the intended site ofaction.

Four-helix bundle cytokines that bind to cytokine receptors as well asother proteins produced by activated lymphocytes play an importantbiological role in cell differentiation, activation, recruitment andhomeostasis of cells throughout the body. Therapeutic utility includestreatment of diseases which require immune regulation includingautoimmune diseases, such as, rheumatoid arthritis, multiple sclerosis,myasthenia gravis, systemic lupus erythomatosis and diabetes. Zcytor17receptor antagonists or agonists, including soluble receptors,anti-receptor antibodies, and the natural ligand, may be important inthe regulation of inflammation, and therefore would be useful intreating rheumatoid arthritis, asthma, ulcerative colitis, inflammatorybowel disease, Crohn's disease, and sepsis. There may be a role ofzcytor17 antagonists or agonists, including soluble receptors,anti-receptor antibodies and the natural ligand, in mediatingtumorgenesis, and therefore would be useful in the treatment of cancer.Zcytor17 antagonists or agonists, including soluble receptors,anti-receptor antibodies and the natural ligand, may be a potentialtherapeutic in suppressing the immune system which would be importantfor reducing graft rejection or in prevention of graft vs. host disease.

Alternatively, zcytor17 antagonists or agonists, including solublereceptors, anti- zcytor17 receptor antibodies and the natural ligand mayactivate the immune system which would be important in boosting immunityto infectious diseases, treating immunocompromised patients, such asHIV+ patient, or in improving vaccines. In particular, zcytor17antagonists or agonists, including soluble receptors and the naturalligand can modulate, stimulate or expand NK cells, or their progenitors,and would provide therapeutic value in treatment of viral infection, andas an anti-neoplastic factor. NK cells are thought to play a major rolein elimination of metastatic tumor cells and patients with bothmetastases and solid tumors have decreased levels of NK cell activity(Whiteside et. al., Curr. Top. Microbiol. Immunol. 230:221-244, 1998).

Polynucleotides encoding zcytor17 polypeptides are useful within genetherapy applications where it is desired to increase or inhibit zcytor17activity. If a mammal has a mutated or absent zcytor17 gene, thezcytor17 gene can be introduced into the cells of the mammal. In oneembodiment, a gene encoding a zcytor17 polypeptide is introduced in vivoin a viral vector. Such vectors include an attenuated or defective DNAvirus, such as, but not limited to, herpes simplex virus (HSV),papillomavirus, Epstein Barr virus (EBV), adenovirus, adeno-associatedvirus (AAV), and the like. Defective viruses, which entirely or almostentirely lack viral genes, are preferred. A defective virus is notinfective after introduction into a cell. Use of defective viral vectorsallows for administration to cells in a specific, localized area,without concern that the vector can infect other cells. Examples ofparticular vectors include, but are not limited to, a defective herpessimplex virus 1 (HSV1) vector (Kaplitt et al., Molec. Cell. Neurosci.2:320-30, 1991); an attenuated adenovirus vector, such as the vectordescribed by Stratford-Perricaudet et al., J. Clin. Invest. 90:626-30,1992; and a defective adeno-associated virus vector (Samulski et al., J.Virol. 61:3096-101, 1987; Samulski et al., J. Virol. 63:3822-8, 1989).

In another embodiment, a zcytor17 gene can be introduced in a retroviralvector, e.g., as described in Anderson et al., U.S. Pat. No. 5,399,346;Mann et al. Cell 33:153, 1983; Temin et al., U.S. Pat. No. 4,650,764;Temin et al., U.S. Pat. No. 4,980,289; Markowitz et al., J. Virol.62:1120, 1988; Temin et al., U.S. Pat. No. 5,124,263; InternationalPatent Publication No. WO 95/07358, published Mar. 16, 1995 by Doughertyet al.; and Kuo et al., Blood 82:845, 1993. Alternatively, the vectorcan be introduced by lipofection in vivo using liposomes. Syntheticcationic lipids can be used to prepare liposomes for in vivotransfection of a gene encoding a marker (Felgner et al., Proc. Natl.Acad. Sci. USA 84:7413-7, 1987; Mackey et al., Proc. Natl. Acad. Sci.USA 85:8027-31, 1988). The use of lipofection to introduce exogenousgenes into specific organs in vivo has certain practical advantages.Molecular targeting of liposomes to specific cells represents one areaof benefit. More particularly, directing transfection to particularcells represents one area of benefit. For instance, directingtransfection to particular cell types would be particularly advantageousin a tissue with cellular heterogeneity, such as the pancreas, liver,kidney, and brain. Lipids may be chemically coupled to other moleculesfor the purpose of targeting. Targeted peptides (e.g., hormones orneurotransmitters), proteins such as antibodies, or non-peptidemolecules can be coupled to liposomes chemically.

It is possible to remove the target cells from the body; to introducethe vector as a naked DNA plasmid; and then to re-implant thetransformed cells into the body. Naked DNA vectors for gene therapy canbe introduced into the desired host cells by methods known in the art,e.g., transfection, electroporation, microinjection, transduction, cellfusion, DEAE dextran, calcium phosphate precipitation, use of a gene gunor use of a DNA vector transporter. See, e.g., Wu et al., J. Biol. Chem.267:963-7, 1992; Wu et al., J. Biol. Chem. 263:14621-4, 1988.

Antisense methodology can be used to inhibit zcytor17 genetranscription, such as to inhibit cell proliferation in vivo.Polynucleotides that are complementary to a segment of azcytor17-encoding polynucleotide (e.g., a polynucleotide as set froth inSEQ ID NO:1, SEQ ID NO:45, SEQ ID NO:53, or SEQ ID NO:57) are designedto bind to zcytor17-encoding mRNA and to inhibit translation of suchmRNA. Such antisense polynucleotides are used to inhibit expression ofzcytor17 polypeptide-encoding genes in cell culture or in a subject.

In addition, as a cell surface molecule, zcytor17 polypeptides can beused as a target to introduce gene therapy into a cell. This applicationwould be particularly appropriate for introducing therapeutic genes intocells in which zcytor17 is normally expressed, such as lymphoid tissue,bone marrow, prostate, thyroid, monocytes and PBLs, or cancer cellswhich express zcytor17 polypeptide. For example, viral gene therapy,such as described above, can be targeted to specific cell types in whichexpress a cellular receptor, such as zcytor17 polypeptide, rather thanthe viral receptor. Antibodies, or other molecules that recognizezcytor17 molecules on the target cell's surface can be used to directthe virus to infect and administer gene therapeutic material to thattarget cell. See, Woo, S. L. C, Nature Biotech. 14:1538, 1996; Wickham,T. J. et al, Nature Biotech. 14:1570-1573, 1996; Douglas, J. T et al.,Nature Biotech. 14:1574-1578, 1996; Rihova, B., Crit. Rev. Biotechnol.17:149-169, 1997; and Vile, R. G. et al., Mol. Med. Today 4:84-92, 1998.For example, a bispecific antibody containing a virus-neutralizing Fabfragment coupled to a zcytor17-specific antibody can be used to directthe virus to cells expressing the zcytor17 receptor and allow efficiententry of the virus containing a genetic element into the cells. See, forexample, Wickham, T. J., et al., J. Virol. 71:7663-7669, 1997; andWickham, T. J., et al., J. Virol. 70:6831-6838, 1996.

Moreover, anti-zcytor17 antibodies and binding frangments can be usedfor tagging and sorting cells that specifically-express Zcytor17, suchas mononuclear cells, lymphoid cells, e.g, non-activated and activatedmonocyte cells, such as activated CD3+, CD4+ and CD8+ cells, CD19+B-cells, and other cells, described herein. Such methods of cell taggingand sorting are well known in the art (see, e.g., “Molecular Biology ofthe Cell”, 3^(rd) Ed., Albert, B. et al. (Garland Publishing, London &New York, 1994). One of skill in the art would recognize the importanceof separating cell tissue types to study cells, and the use ofantibodies to separate specific cell tissue types. Basically, antibodiesthat bind to the surface of a cell type are coupled to various matricessuch as collagen, polysaccharide beads, or plastic to form an affinitysurface to which only cells recognized by the antibodies will adhere.The bound cells are then recovered by conventional techniques. Othermethods involve separating cells by a fluorescence-activated cell sorter(FACS). In this technique one labels cells with antibodies that arecoupled to a fluorescent dye. The labeled cells are then separated fromunlabeled cells in a FACS machine. In FACS sorting individual cellstraveling in single file pass through a laser beam and the fluorescenceof each cell is measured. Slightly further down-stream, tiny droplets,most containing either one or no cells, are formed by a vibratingnozzle. The droplets containing a single cell are automatically give apositive or negative charge at the moment of formation, depending onwhether the cell they contain is fluorescent, and then deflected by astrong electric field into an appropriate container. Such machines canselect 1 cell in 1000 and sort about 5000 cells each second. Thisproduces a uniform population of cells for cell culture.

One of skill in the art would recognize that the antibodies to theZcytor17 polypeptides of the present invention are useful, because notall tissue types express the Zcytor17 receptor and because it isimportant that biologists be able to separate specific cell types forfurther study and/or therapeutic re-implantation into the body. This isparticularly relevant in cells such as immune cells, wherein zcytor17 isexpressed.

The present invention also provides reagents that will find use indiagnostic applications. For example, the zcytor17 gene, a probecomprising zcytor17 DNA or RNA or a subsequence thereof can be used todetermine if the zcytor17 gene is present on chromosome 5 or if amutation has occurred. Zcytor17 is located at the 5q11 region ofchromosome 5 (See, Example 4). Detectable chromosomal aberrations at thezcytor17 gene locus include, but are not limited to, aneuploidy, genecopy number changes, loss of heterogeneity (LOH), translocations,insertions, deletions, restriction site changes and rearrangements. Suchaberrations can be detected using polynucleotides of the presentinvention by employing molecular genetic techniques, such as restrictionfragment length polymorphism (RFLP) analysis, fluorescence in situhybridization methods, short tandem repeat (STR) analysis employing PCRtechniques, and other genetic linkage analysis techniques known in theart (Sambrook et al., ibid.; Ausubel et. al., ibid.; Marian, Chest108:255-65, 1995).

The precise knowledge of a gene's position can be useful for a number ofpurposes, including: 1) determining if a sequence is part of an existingcontig and obtaining additional surrounding genetic sequences in variousforms, such as YACs, BACs or cDNA clones; 2) providing a possiblecandidate gene for an inheritable disease which shows linkage to thesame chromosomal region; and 3) cross-referencing model organisms, suchas mouse, which may aid in determining what function a particular genemight have.

The zcytor17 gene is located at the 5q11 region of chromosome 5. Severalgenes of known function map to this region. For example, a closelyrelated class I cytokine receptor, gp130, also maps chromosome 5q11suggesting that the 5q11 region is an important region for cytokinereceptor expression. Zcytor17 maps in the 5q11 chromosomal region (firstregion distal of the centromere on the q-arm) and gp130 appears to beabout 920.7 kb distal of Zcytor 17. Moreover, the closely related classI cytokine receptor LIFR maps just on the other side of the centromereon the p-arm in the 5p13-p12 region. The gp130 cytokine receptor isshared by several other cytokine receptors to form heterodimericcomplexes, that enable signaling by cytokines such as IL-6, leukemiainhibitory factor (LIF), oncostatin M (OSM), and ciliary neurotropicfactor (CNTF). Moreover, gp130 may form a heterodimeric, trimeric (e.g.,with gp130+ LIF receptor), or multimeric complex with the zcytor17polypeptide in order to signal. Moreover, as discussed herein, cytokinereceptors such as zcytor17 and gp130 play important roles in immune cellfunction, proliferation, migration, inflammation and the like. As such,zcytor17 polynucleotides, polypeptides, and anti-zcytor17 antibodiesserve an important use as a diagnostic to detect defects in the zcytor17gene or protein, or defects in surrounding chromosomal regions at the5q11 region of chromosome 5.

Moreover, several disease-related genes cluster in the 5q11 region thatare associated with human disorders. One of skill in the art wouldrecognize that a marker in 5q11 such as the zcytor17 polynucleotides ofthe present invention, would be useful in detecting chromosomalaberrations associated with human disease, since aberrations in andaround 5q11 are known to be linked to human disease. For example,5q11-q13.3 duplications, partial trisomy, and translocations, areassociated with multiple anomalies including schizophrenia, a commonpsychosis. In addition, Maroteaux-Lamy Syndrome, or mucopolysaccaridosistypes VI (5q11-q13) and Klippel-Feil syndrome (5q11.2) are associatedwith translocation at this locus. In addition, these diseases are linkedto large chromosomal rearrangements, such as chromosome duplication,translocation or loss of heterogeneity in the 5q11 region chromosome 5.Using, for example, polynucleotides of the present invention inconjunction with known methods in the art described herein, suchrearrangements at or around 5q11 can be detected. Moreover, amongstother genetic loci, those for split-hand/foot malformation, type 1(SHFM1) (5q), Sandhoff disease (5q13), glucocorticoid receptor (5q31),dihydrofolate reductase (DHFBR) (5q11.2-q13.2) spinal muscular atrophy(5q12.2-q13.3) and Pituitary Hormone Deficiency (5q) all manifestthemselves in human disease states as well as map to this region of thehuman genome. See the Online Mendellian Inheritance of Man (OMIM™,National Center for Biotechnology Information, National Library ofMedicine. Bethesda, Md.) gene map, and references therein, for thisregion of chromosome 5 on a publicly available WWW server(http://www3.ncbi.nlm.nih.gov/htbin -post/Omim/getmap?chromosome=5q11and surrounding loci). All of these serve as possible candidate genesfor an inheritable disease that show linkage to the same chromosomalregion as the zcytor17 gene.

Similarly, defects in the zcytor17 locus itself may result in aheritable human disease states as discussed herein. One of skill in theart would appreciate that defects in cytokine receptors are known tocause disease states in humans. For example, growth hormone receptormutation results in dwarfism (Amselem, S et al., New Eng. J. Med. 321:989-995, 1989), IL-2 receptor gamma mutation results in severe combinedimmunodeficiency (SCID) (Noguchi, M et al., Cell 73: 147-157, 1993),c-Mpl mutation results in thrombocytopenia (Ihara, K et al., Proc. Nat.Acad. Sci. 96: 3132-3136, 1999), and severe mycobacterial and Salmonellainfections result in interleukin-12 receptor-deficient patients (deJong, R et al., Science 280: 1435-1438, 1998), amongst others. Thus,similarly, defects in zcytor17 can cause a disease state orsusceptibility to disease or infection. As the zcytor17 gene is locatedat the 5q11 region zcytor17, polynucleotide probes can be used to detectchromosome 5q11 loss, trisomy, duplication or translocation associatedwith human diseases, such as immune cell cancers, bone marrow cancers,prostate cancer, thyroid, parathyroid or other cancers, or immunediseases. Moreover, molecules of the present invention, such as thepolypeptides, antagonists, agonists, polynucleotides and antibodies ofthe present invention would aid in the detection, diagnosis prevention,and treatment associated with a zcytor17 genetic defect.

Molecules of the present invention, such as the polypeptides,antagonists, agonists, polynucleotides and antibodies of the presentinvention would aid in the detection, diagnosis prevention, andtreatment associated with a zcytor17 genetic defect.

A diagnostic could assist physicians in determining the type of diseaseand appropriate associated therapy, or assistance in genetic counseling.As such, the inventive anti-zcytor17 antibodies, polynucleotides, andpolypeptides can be used for the detection of zcytor17 polypeptide, mRNAor anti-zcytor17 antibodies, thus serving as markers and be directlyused for detecting or genetic diseases or cancers, as described herein,using methods known in the art and described herein. Further, zcytor17polynucleotide probes can be used to detect abnormalities or genotypesassociated with chromosome 5q11 deletions and translocations associatedwith human diseases, other translocations involved with malignantprogression of tumors or other 5q11 mutations, which are expected to beinvolved in chromosome rearrangements in malignancy; or in othercancers, or in spontaneous abortion. Similarly, zcytor17 polynucleotideprobes can be used to detect abnormalities or genotypes associated withchromosome 5q11 trisomy and chromosome loss associated with humandiseases or spontaneous abortion. Thus, zcytor17 polynucleotide probescan be used to detect abnormalities or genotypes associated with thesedefects.

As discussed above, defects in the zcytor17 gene itself may result in aheritable human disease state. Molecules of the present invention, suchas the polypeptides, antagonists, agonists, polynucleotides andantibodies of the present invention would aid in the detection,diagnosis prevention, and treatment associated with a zcytor17 geneticdefect. In addition, zcytor17 polynucleotide probes can be used todetect allelic differences between diseased or non-diseased individualsat the zcytor17 chromosomal locus. As such, the zcytor17 sequences canbe used as diagnostics in forensic DNA profiling.

In general, the diagnostic methods used in genetic linkage analysis, todetect a genetic abnormality or aberration in a patient, are known inthe art. Analytical probes will be generally at least 20 nt in length,although somewhat shorter probes can be used (e.g., 14-17 nt). PCRprimers are at least 5 nt in length, preferably 15 or more, morepreferably 20-30 nt. For gross analysis of genes, or chromosomal DNA, azcytor17 polynucleotide probe may comprise an entire exon or more. Exonsare readily determined by one of skill in the art by comparing zcytor17sequences (e.g., SEQ ID NO:54) with the human genomic DNA for zcytor17(Genbank Accession No. AQ002781). In general, the diagnostic methodsused in genetic linkage analysis, to detect a genetic abnormality oraberration in a patient, are known in the art. Most diagnostic methodscomprise the steps of (a) obtaining a genetic sample from a potentiallydiseased patient, diseased patient or potential non-diseased carrier ofa recessive disease allele; (b) producing a first reaction product byincubating the genetic sample with a zcytor17 polynucleotide probewherein the polynucleotide will hybridize to complementarypolynucleotide sequence, such as in RFLP analysis or by incubating thegenetic sample with sense and antisense primers in a PCR reaction underappropriate PCR reaction conditions; (iii) Visualizing the firstreaction product by gel electrophoresis and/or other known method suchas visualizing the first reaction product with a zcytor17 polynucleotideprobe wherein the polynucleotide will hybridize to the complementarypolynucleotide sequence of the first reaction; and (iv) comparing thevisualized first reaction product to a second control reaction productof a genetic sample from wild type patient. A difference between thefirst reaction product and the control reaction product is indicative ofa genetic abnormality in the diseased or potentially diseased patient,or the presence of a heterozygous recessive carrier phenotype for anon-diseased patient, or the presence of a genetic defect in a tumorfrom a diseased patient, or the presence of a genetic abnormality in afetus or pre-implantation embryo. For example, a difference inrestriction fragment pattern, length of PCR products, length ofrepetitive sequences at the zcytor17 genetic locus, and the like, areindicative of a genetic abnormality, genetic aberration, or allelicdifference in comparison to the normal wild type control. Controls canbe from unaffected family members, or unrelated individuals, dependingon the test and availability of samples. Genetic samples for use withinthe present invention include genomic DNA, mRNA, and cDNA isolated formany tissue or other biological sample from a patient, such as but notlimited to, blood, saliva, semen, embryonic cells, amniotic fluid, andthe like. The polynucleotide probe or primer can be RNA or DNA, and willcomprise a portion of SEQ ID NO:1, SEQ ID NO:45 or SEQ ID NO:53, thecomplement of SEQ ID NO:1, SEQ ID NO:45 or SEQ ID NO:53, or an RNAequivalent thereof. Such methods of showing genetic linkage analysis tohuman disease phenotypes are well known in the art. For reference to PCRbased methods in diagnostics see see, generally, Mathew (ed.), Protocolsin Human Molecular Genetics (Humana Press, Inc. 1991), White (ed.), PCRProtocols: Current Methods and Applications (Humana Press, Inc. 1993),Cotter (ed.), Molecular Diagnosis of Cancer (Humana Press, Inc. 1996),Hanausek and Walaszek (eds.), Tumor Marker Protocols (Humana Press, Inc.1998), Lo (ed.), Clinical Applications of PCR (Humana Press, Inc. 1998),and Meltzer (ed.), PCR in Bioanalysis (Humana Press, Inc. 1998)).

Mutations associated with the zcytor17 locus can be detected usingnucleic acid molecules of the present invention by employing standardmethods for direct mutation analysis, such as restriction fragmentlength polymorphism analysis, short tandem repeat analysis employing PCRtechniques, amplification-refractory mutation system analysis,single-strand conformation polymorphism detection, RNase cleavagemethods, denaturing gradient gel electrophoresis, fluorescence-assistedmismatch analysis, and other genetic analysis techniques known in theart (see, for example, Mathew (ed.), Protocols in Human MolecularGenetics (Humana Press, Inc. 1991), Marian, Chest 108:255 (1995),Coleman and Tsongalis, Molecular Diagnostics (Human Press, Inc. 1996),Elles (ed.) Molecular Diagnosis of Genetic Diseases (Humana Press, Inc.1996), Landegren (ed.), Laboratory Protocols for Mutation Detection(Oxford University Press 1996), Birren et al. (eds.), Genome Analysis,Vol. 2: Detecting Genes (Cold Spring Harbor Laboratory Press 1998),Dracopoli et al. (eds.), Current Protocols in Human Genetics (John Wiley& Sons 1998), and Richards and Ward, “Molecular Diagnostic Testing,” inPrinciples of Molecular Medicine, pages 83-88 (Humana Press, Inc.1998)). Direct analysis of an zcytor17 gene for a mutation can beperformed using a subject's genomic DNA. Methods for amplifying genomicDNA, obtained for example from peripheral blood lymphocytes, arewell-known to those of skill in the art (see, for example, Dracopoli etal. (eds.), Current Protocols in Human Genetics, at pages 7.1.6 to 7.1.7(John Wiley & Sons 1998)).

Mice engineered to express the zcytor17 gene, referred to as “transgenicmice,” and mice that exhibit a complete absence of zcytor17 genefunction, referred to as “knockout mice,” may also be generated(Snouwaert et al., Science 257:1083, 1992; Lowell et al., Nature366:740-42, 1993; Capecchi, M. R., Science 244: 1288-1292, 1989;Palmiter, R. D. et al. Annu Rev Genet. 20: 465-499, 1986). For example,transgenic mice that over-express zcytor17, either ubiquitously or undera tissue-specific or tissue-restricted promoter can be used to askwhether over-expression causes a phenotype. For example, over-expressionof a wild-type zcytor17 polypeptide, polypeptide fragment or a mutantthereof may alter normal cellular processes, resulting in a phenotypethat identifies a tissue in which zcytor17 expression is functionallyrelevant and may indicate a therapeutic target for the zcytor17, itsagonists or antagonists. For example, a preferred transgenic mouse toengineer is one that expresses a “dominant-negative” phenotype, such asone that over-expresses the zcytor17 polypeptide comprising anextracellular cytokine binding domain with the transmembrane domainattached (approximately amino acids 20 (Ala) to 543 (Leu) of SEQ ID NO:2and SEQ ID NO:46; or 33 (Ala) to 556 (Leu) of SEQ ID NO:54). Anotherpreferred transgenic mouse is one that over-expresses zcytor17 solublereceptors, such as those disclosed herein. Moreover, suchover-expression may result in a phenotype that shows similarity withhuman diseases. Similarly, knockout zcytor17 mice can be used todetermine where zcytor17 is absolutely required in vivo. The phenotypeof knockout mice is predictive of the in vivo effects of a zcytor17antagonist, such as those described herein, may have. The mouse zcytor17mRNA, cDNA (SEQ ID NO:56 and/or SEQ ID NO:92) and genomic DNA, are usedto generate knockout mice. These transgenic and knockout mice may beemployed to study the zcytor17 gene and the protein encoded thereby inan in vivo system, and can be used as in vivo models for correspondinghuman or animal diseases (such as those in commercially viable animalpopulations). The mouse models of the present invention are particularlyrelevant as, immune system models, inflammation or tumor models for thestudy of cancer biology and progression. Such models are useful in thedevelopment and efficacy of therapeutic molecules used in human immunediseases, inflammation and cancers. Because increases in zcytor17expression, as well as decreases in zcytor17 expression are associatedwith monocytes, monocyte activation, and prostate cells, and may beassociated with inflammation and cancers, both transgenic mice andknockout mice would serve as useful animal models for human disease.Moreover, in a preferred embodiment, zcytor17 transgenic mouse can serveas an animal model for specific diseases, particularly those associatedwith monocytes. Moreover, transgenic mice expression of zcytor17antisense polynucleotides or ribozymes directed against zcytor17,described herein, can be used analogously to transgenic mice describedabove.

For pharmaceutical use, the soluble receptor polypeptides of the presentinvention are formulated for parenteral, particularly intravenous orsubcutaneous, delivery according to conventional methods. Intravenousadministration will be by bolus injection or infusion over a typicalperiod of one to several hours. In general, pharmaceutical formulationswill include a zcytor17 soluble receptor polypeptide in combination witha pharmaceutically acceptable vehicle, such as saline, buffered saline,5% dextrose in water or the like. Formulations may further include oneor more excipients, preservatives, solubilizers, buffering agents,albumin to prevent protein loss on vial surfaces, etc. Methods offormulation are well known in the art and are disclosed, for example, inRemington: The Science and Practice of Pharmacy, Gennaro, ed., MackPublishing Co., Easton, Pa., 19th ed., 1995. Therapeutic doses willgenerally be in the range of 0.1 to 100 μg/kg of patient weight per day,preferably 0.5-20 mg/kg per day, with the exact dose determined by theclinician according to accepted standards, taking into account thenature and severity of the condition to be treated, patient traits, etc.Determination of dose is within the level of ordinary skill in the art.The proteins may be administered for acute treatment, over one week orless, often over a period of one to three days or may be used in chronictreatment, over several months or years. In general, a therapeuticallyeffective amount of zcytor17 soluble receptor polypeptide is an amountsufficient to produce a clinically significant effect.

Polynucleotides and polypeptides of the present invention willadditionally find use as educational tools as a laboratory practicumkits for courses related to genetics and molecular biology, proteinchemistry and antibody production and analysis. Due to its uniquepolynucleotide and polypeptide sequence molecules of zcytor17 can beused as standards or as “unknowns” for testing purposes. For example,zcytor17 polynucleotides can be used as an aid, such as, for example, toteach a student how to prepare expression constructs for bacterial,viral, and/or mammalian expression, including fusion constructs, whereinzcytor17 is the gene to be expressed; for determining the restrictionendonuclease cleavage sites of the polynucleotides; determining mRNA andDNA localization of zcytor17 polynucleotides in tissues (i.e., byNorthern and Southern blotting as well as polymerase chain reaction);and for identifying related polynucleotides and polypeptides by nucleicacid hybridization.

Zcytor17 polypeptides can be used educationally as an aid to teachpreparation of antibodies; identifying proteins by Western blotting;protein purification; determining the weight of expressed zcytor17polypeptides as a ratio to total protein expressed; identifying peptidecleavage sites; coupling amino and carboxyl terminal tags; amino acidsequence analysis, as well as, but not limited to monitoring biologicalactivities of both the native and tagged protein (i.e., receptorbinding, signal transduction, proliferation, and differentiation) invitro and in vivo. Zcytor17 polypeptides can also be used to teachanalytical skills such as mass spectrometry, circular dichroism todetermine conformation, especially of the four alpha helices, x-raycrystallography to determine the three-dimensional structure in atomicdetail, nuclear magnetic resonance spectroscopy to reveal the structureof proteins in solution. For example, a kit containing the zcytor17 canbe given to the student to analyze. Since the amino acid sequence wouldbe known by the professor, the specific protein can be given to thestudent as a test to determine the skills or develop the skills of thestudent, the teacher would then know whether or not the student hascorrectly analyzed the polypeptide. Since every polypeptide is unique,the educational utility of zcytor17 would be unique unto itself.

Moreover, since zcytor17 has a tissue-specific expression and is apolypeptide with a class I cytokine receptor structure and a distinctchromosomal localization, and expression pattern, activity can bemeasured using proliferation assays; luciferase and binding assaysdescribed herein. Moreover, expression of zcytor17 polynucleotides andpolypeptides in monocyte, prostate, lymphoid and other tissues can beanalyzed in order to train students in the use of diagnostic andtissue-specific identification and methods. Moreover zcytor17polynucleotides can be used to train students on the use of chromosomaldetection and diagnostic methods, since it's locus is known. Moreover,students can be specifically trained and educated about human chromosome1, and more specifically the locus 5q11 wherein the zcytor17 gene islocalized. Such assays are well known in the art, and can be used in aneducational setting to teach students about cytokine receptor proteinsand examine different properties, such as cellular effects on cells,enzyme kinetics, varying antibody binding affinities, tissuespecificity, and the like, between zcytor17 and other cytokine receptorpolypeptides in the art.

The antibodies which bind specifically to zcytor17 can be used as ateaching aid to instruct students how to prepare affinity chromatographycolumns to purify zcytor17, cloning and sequencing the polynucleotidethat encodes an antibody and thus as a practicum for teaching a studenthow to design humanized antibodies. Moreover, antibodies that bindspecifically to zcytor17 can be used as a teaching aid for use indetection e.g., of activated monocyte cells, cell sorting, or lymphoidand prostate cancer tissue using histological, and in situ methodsamongst others known in the art. The zcytor17 gene, polypeptide orantibody would then be packaged by reagent companies and sold touniversities and other educational entities so that the students gainskill in art of molecular biology. Because each gene and protein isunique, each gene and protein creates unique challenges and learningexperiences for students in a lab practicum. Such educational kitscontaining the zcytor17 gene, polypeptide or antibody are consideredwithin the scope of the present invention.

The invention is further illustrated by the following non-limitingexamples.

EXAMPLES Example 1 Identification and Isolation of Full-length HumanZcytor17 cDNA

Zcytor18 was identified as a predicted full-length cDNA from humangenomic DNA. The sequence of the predicted full length zcytor17polynucleotide is shown in SEQ ID NO:1 and the corresponding polypeptideis shown in SEQ ID NO:2. To obtain a full-length cDNA from a tissuesource, 5′ and 3′ RACE were employed. Several oligonucleotide primerswere designed from the identified genomic sequence AQ002781 (Genbank).The primers were used for priming internally within the genomic sequenceto ultimately isolate a full-length cDNA.

A. 5′ RACE for Zcytor17

A 5′ RACE product was generated using an HPVS cDNA library as a templateand oligonucleotides ZC12,701 (SEQ ID NO:5) and ZC27,898 (SEQ ID NO:6)as primers. HPVS is an in-house cDNA library generated from a humanprostate epithelial cell line (ATCC No. CRL-2221). The PCR reaction usedapproximately 1 μg of of plasmid DNA prepared from the cDNA library as atemplate, 5 μl of 10×PCR buffer (GIBCO/BRL), 5 μl of 10 mM dNTPs (PerkinElmer), 20 pmol each oligonucleotide, and 1 pl (5.0 units) Taqpolymerase (GIBCO/BRL) in a 50 ul reaction volume. This first-round 5′RACE PCR reaction was run as follows: 30 cycles at 94° C. for 1 minute,65° C. for 1 minute, 72° C. for 2 minutes, then 72° C. for 7 minutes; 4°C. soak. An aliquot of 5′ RACE PCR product was removed and analyzed on a1.0% agarose gel. Multiple bands were seen on the gel.

The remaining 5′ RACE PCR product was ethanol precipitated and diluted1:50. A second-round nested 5′ RACE PCR reaction was run to amplifytemplate cDNA sequence. This PCR reaction used oligonucleotides ZC14,063(SEQ ID NO:7) and ZC27,899 (SEQ ID NO:8), which were designed to annealto sequence internal of ZC12,701 (SEQ ID NO:5) and ZC27,898 (SEQ IDNO:6). This nested PCR reaction was run as per the first-round 5′ RACEreaction disclosed above. The resulting DNA products wereelectrophoresed on a 1.0% agarose gel and a prominent band atapproximately 900 bp was seen. The DNA band was gel purified andsequenced using standard methods. Sequence analyses revealed that theDNA product included part of the genomic AQ002781 DNA sequence (Genbank)and appeared to extend the cDNA sequence for zcytor17 on the 5′ end toinclude a translation initiating methionine residue and some 5′untranslated sequence. The polynucleotide sequence of the 5′ RACEproduct is shown in SEQ ID NO:9.

B. 3′ RACE for Zcytor17

Primers for 3′ RACE were designed using the 5′ RACE product (SEQ IDNO:9) obtained above. A 3′ RACE product was generated using a humanprostate in-house cDNA library as a template and oligonucleotidesZC28,481 (SEQ ID NO: 10) and ZC6,346 (SEQ ID NO:11) as primers. Thisfirst-round 3′ RACE PCR reaction was run under the conditions describedin Example 1A. An aliquot of 3′ RACE PCR product was removed andanalyzed on a 1.0% agarose gel. Multiple bands were seen on the gel.

The remaining 3′ RACE PCR product was ethanol precipitated and diluted1:40. A second-round nested 3′ RACE PCR reaction was run to amplifytemplate cDNA sequence. This PCR reaction used oligonucleotides ZC28,480(SEQ ID NO:12) and ZC26,405 (SEQ ID NO:13), which were designed toanneal to sequence internal of ZC28,481 (SEQ ID NO:10) and ZC6,346 (SEQID NO:11). This nested PCR reaction was run as disclosed above. Theresulting DNA products were electrophoresed on a 1.0% agarose gel and aprominent band at approximately 2100 bp was seen.

The remaining DNA was ethanol precipitated and diluted 1:40. Athird-round nested 3′ RACE PCR reaction was run to amplify template cDNAsequence. This PCR reaction used oligonucleotides ZC27,895 (SEQ IDNO:14) and ZC5,020 (SEQ ID NO:15), which were designed to anneal tosequence internal of ZC28,480 (SEQ ID NO:12) and ZC26,405 (SEQ IDNO:13). This nested PCR reaction was run as disclosed above. Theresulting PCR products were electrophoresed on a 1.0% agarose gel and aprominent band at approximately 2000 bp was seen. The DNA band was gelpurified and sequenced. Sequence analyses revealed that the DNA productincluded part of the 5′ RACE product (SEQ ID NO:9) and appeared toextend the cDNA sequence for zcytor17 on the 3′ end to include atranslation stop codon and some 3′ untranslated sequence. Thepolynucleotide sequence of the 3′ RACE product is shown in SEQ ID NO:16.The polynucleotide sequence of the full-length zcytor17 is shown in SEQID NO:45 and the corresponding polypeptide sequence is shown in SEQ IDNO:46.

C. A second 5′ RACE for Zcytor17 Identified an Alternative Full-lengthZcytor17

A 5′ RACE product was generated using a WI-38 cDNA library as a templateand oligonucleotides ZC12,701 (SEQ ID NO:5)and ZC27,899 (SEQ ID NO:8) asprimers. WI-28 is an in-house cDNA library generated from a humanembryonic lung cell line (ATCC No. CRL-75). The PCR reaction usedapproximately 1 μg of of plasmid DNA prepared from the cDNA library as atemplate, 5 μl of 10×PCR buffer (GIBCO/BRL), 5 μl of 10 mM dNTPs (PerkinElmer), 20 pmol each oligonucleotide, and 1 μl (5.0 units) Taqpolymerase (GIBCO/BRL) in a 50 μl reaction volume. This first-round 5′RACE PCR reaction was run as follows: 30 cycles at 94° C. for 1 minute,65° C. for 1 minute, 72° C. for 2 minutes, then 72° C. for 7 minutes; 4°C. soak. An aliquot of 5′ RACE PCR product was removed and analyzed on a1.0% agarose gel. Multiple bands were seen on the gel.

The remaining DNA was ethanol precipitated and diluted 1:50. Asecond-round nested 5′ RACE PCR reaction was run to amplify templatecDNA sequence. This PCR reaction used oligonucleotides ZC14,063 (SEQ IDNO:25), and ZC27,900 (SEQ ID NO:51), which were designed to anneal tosequence internal of ZC12,701 (SEQ ID NO:51) and ZC27,899 (SEQ ID NO:8).This nested PCR reaction was run as per the first-round 5′ RACE reactiondisclosed above. The resulting DNA products were electrophoresed on a1.0% agarose gel and a prominent band at approximately 1200 bp was seen.The DNA band was gel purified and sequenced. Sequence analyses revealedthat the DNA product included part of the genomic DNA sequence AQ002781(Genbank) and appeared to extend the cDNA sequence for zcytor17 on the5′ end to include a translation initiating methionine residue and some5′ untranslated sequence. DNA sequencing showed that the polypeptidegenerated from translation from this alternative initiating methionine(shown in SEQ ID NO:53 at nucleotide 497) generates a second full-lengthform of zcytor17 that differs by an additional 13 amino acids in-frameat the N-terminus (MKLSPQPSCVNLG; SEQ ID NO:52) from that shown in SEQID NO:46. The polynucleotide sequence of the second full-length form ofzcytor17 is shown in SEQ ID NO:53 and the corresponding polypeptidesequence is shown in SEQ ID NO:54. The second full-length form ofzcytor17 (SEQ ID NO:53 and SEQ ID NO:54) is likely the most commonlyexpressed form.

Example 2 Identification and Isolation of Truncated Forms Human zcytor17cDNA

A. Isolation of a cDNA Coding for a Variant form of Zcytor17 truncatedat the Fibronectin Domain

A 3′ RACE product for a truncated soluble form of zcytor17 was generatedusing a protocol identical to that described above for 3′ RACE (Example1B), except that the starting material was the HPVS cDNA library. HPVSis an in-house cDNA library generated from a human prostate epithelialcell line (ATCC No. CRL-2221). The resulting products from the thirdround nested 3′ RACE were electrophoresed on a 1.0% agarose gel and aprominent band at approximately 700 bp was seen. The DNA band was gelpurified and sequenced. Sequence analyses revealed that the DNA productincluded part of the 5′ RACE product (SEQ ID NO:9) and appeared toextend the cDNA sequence for zcytor17 to include a translation stopcodon near the end of the cytokine-binding domain. This could representan expressed soluble form of the receptor truncated within thefibronectin domain. The polynucleotide sequence of the soluble form ofzcytor17 truncated within the fibronectin domain is shown in SEQ IDNO:15 and the corresponding polypeptide sequence is shown in SEQ IDNO:18.

B. Isolation of a cDNA Coding for a form of Zcytor17 Truncated at theEnd of the Cytokine-binding Domain

A 3′ RACE product for a truncated form of zcytor17 was generated usingthe HPVS cDNA library as a template and ZC27,895 (SEQ ID NO: 14) andZC6,346 (SEQ ID NO:11) as primers. This first-round 3′ RACE PCR reactionwas run as follows: 30 cycles at 94° C. for 1 minute, 65° C. for 1minute, 72° C. for 2 minutes, then 72° C. for 7 minute; 4° C. soak. Analiquot of 3′ RACE PCR product was removed and analyzed on a 1.0%agarose gel. Multiple bands were seen on the gel.

The remaining DNA was ethanol precipitated and diluted 1:40. Asecond-round nested 3′ RACE PCR reaction was run to amplify templatecDNA sequence. This PCR reaction used oligonucleotides ZC27,897 (SEQ IDNO: 19) and ZC5,020 (SEQ ID NO: 15), which were designed to anneal tosequence internal of ZC27,895 (SEQ ID NO: 14) and ZC6,346 (SEQ ID NO:11). This nested PCR reaction was run as per the first-round 5′ RACEdisclosed in Example 1A, above. The resulting DNA products wereelectrophoresed on a 1.0% agarose gel and a prominent band atapproximately 1100 bp was seen. The DNA band was gel purified andsequenced. Sequence analysis revealed that the DNA product included partof the genomic AQ002781 DNA sequence (Genbank) and appeared to extendthe cDNA sequence for zcytor17 on the 3′ end to include a translationstop codon at the end of the cytokine-binding domain.

To confirm that the above sequence did indeed overlap with the genomicAQ002781 DNA sequence, an additional PCR reaction was performed. A PCRproduct was generated using the HPVS cDNA library as a template andoligonucleotides ZC28,481 (SEQ ID NO: 10) and ZC28,521 (SEQ ID NO:20) asprimers. The PCR reaction was run as follows: 30 cycles at 94° C. for 1minute, 65° C. for 1 minute, 72° C. for 2 minutes, then 7 minutes; 4° C.soak. The resulting DNA products were electrophoresed on a 1.0% agarosegel and a prominent band at approximately 800 bp was seen. The DNA bandwas gel purified and sequenced. Sequence analyses confirmed that thiswas a truncated form of zcytor17. This could represent an expressedsoluble form of the receptor truncated near the end of thecytokine-binding domain. The polynucleotide sequence of this solubleform of zcytor17 is shown in SEQ ID NO:21 and the correspondingpolypeptide sequence is shown in SEQ ID NO:22).

Another truncated 3′ RACE product was isolated using the protocoldescribed above for isolation of a cDNA variant truncated at thefibronectin domain (Example 2A). Sequencing of the isolated PCR productverified the sequence of the soluble form of zcytor17 as shown in SEQ IDNO:21.

Example 3 Tissue Distribution of Human zcytor17 in Tissue Panels UsingNorthern Blot and PCR

A. Human Zcytor17 Tissue Distribution using Northern Blot

Human Multiple Tissue Northern Blots (Human 12-lane MTN Blot I and II,and Human Immune System MTN Blot II; Human Endocrine MTN, Human FetalMTN Blot II, Human Multiple Tissue Array) (Clontech) as well as in houseblots containing various tissues were probed to determine the tissuedistribution of human zcytor17 expression. The in-house prepared blotsincluded the following tissue and cell line mRNA: SK-Hep-1 cells, THP1cells, Adrenal gland (Clontech); Kidney (Clontech), Liver (Clontech andInvitrogen); Spinal cord (Clontech), Testis (Clontech), Human CD4+T-cells, Human CD8+ T-cells, Human CD19+ T-cells, human mixed lymphocytereaction (MLR), THP1 cell line (ATCC No. TIB-202), U937 cell line,p388D1 mouse lymphoblast cell line (ATCC No. CCL-46) with or withoutstimulation by lonomycin; and WI-38 human embryonic lung cell line (ATCCNo. CRL-2221) with or without stimulation by lonomycin.

An approximately 500 bp PCR derived probe was amplified using the 5′RACE (Example 1A) (SEQ ID NO:9) as template and oligonucleotidesZC28,575 (SEQ ID NO:23) and ZC27,899 (SEQ ID NO:24) as primers. The PCRamplification was carried out as follows: 30 cycles of 94° C. for 1minute, 65° C. for 1 minute, and 72° C. for 1 minute; followed by 1cycle at 72° C. for 7 minutes. The PCR product was visualized by agarosegel electrophoresis and the approximately 500 bp PCR product was gelpurified as described herein. The probe was radioactively labeled usingthe PRIME IT II™ Random Primer Labeling Kit (Stratagene) according tothe manufacturer's instructions. The probe was purified using a NUCTRAP™push column (Stratagene). EXPRESSHYB™ (Clontech) solution was used forthe prehybridization and as a hybridizing solution for the Northernblots. Prehybridization was carried out at 68° C. for 2 hours.Hybridization took place overnight at 68° C. with about 1.5×10⁶ cpm/mlof labeled probe. The blots were washed three times at room temperaturein 2×SSC, 0.05% SDS, followed by 1 wash for 10 minutes in 2×SSC, 0.1%SDS at 50° C. Several faint bands were seen after several days exposure.An approximately 9 kb transcript was seen in trachea, skeletal muscleand thymus; an approximately 2 kb transcript was seen in PBL, HPV, U937and THP-1 cells; and about a 1.2 kb transcript was seen in placenta,bone marrow and thyroid, and HPV and U937 cells. In all the tissueslisted above, the signal intensity was faint. There appeared to belittle expression in most normal tissues, suggesting that zcytor17expression may be dependent on activation of the cell or tissues inwhich it is expressed.

Northern analysis is also performed using Human Cancer Cell Line MTNM(Clontech). PCR and probing conditions are as described above. A strongsignal in a cancer line suggests that zcytor17 expression may beexpressed in activated cells and/or may indicate a cancerous diseasestate. Moreover, using methods known in the art, Northern blots or PCRanalysis of activated lymphocyte cells can also show whether zcytor17 isexpressed in activated immune cells.

B. Tissue Distribution in Tissue Panels Using PCR

A panel of cDNAs from human tissues was screened for zcytor17 expressionusing PCR. The panel was made in-house and contained 94 marathon cDNAand cDNA samples from various normal and cancerous human tissues andcell lines is shown in Table 5, below. The cDNAs came from in-houselibraries or marathon cDNAs from in-house RNA preps, Clontech RNA, orInvitrogen RNA. The marathon cDNAs were made using the marathon-Ready™kit (Clontech, Palo Alto, Calif.) and QC tested with clathrin primersZC21195 (SEQ ID NO:49) and ZC21196 (SEQ ID NO:50) and then diluted basedon the intensity of the clathrin band. To assure quality of the panelsamples, three tests for quality control (QC) were run: (1) To assessthe RNA quality used for the libraries, the in-house cDNAs were testedfor average insert size by PCR with vector oligos that were specific forthe vector sequences for an individual cDNA library; (2) Standardizationof the concentration of the cDNA in panel samples was achieved usingstandard PCR methods to amplify full length alpha tubulin or G3PDH cDNAusing a 5′ vector oligo ZC14,063 (SEQ ID NO:25) and 3′ alpha tubulinspecific oligo primer ZC17,574 (SEQ ID NO:26) or 3′ G3PDH specific oligoprimer ZC17,600 (SEQ ID NO:27); and (3) a sample was sent to sequencingto check for possible ribosomal or mitochondrial DNA contamination. Thepanel was set up in a 96-well format that included a human genomic DNA(Clontech, Palo Alto, Calif.) positive control sample. Each wellcontained approximately 0.2-100 pg/μl of cDNA. The PCR reactions wereset up using oligos ZC26,358 (SEQ ID NO:28) and ZC26,359 (SEQ ID NO:29),TaKaRa Ex Taq™ (TAKARA Shuzo Co LTD, Biomedicals Group, Japan), andRediload dye (Research Genetics, Inc., Huntsville, Ala.). Theamplification was carried out as follows: 1 cycle at 94° C. for 2minutes, 35 cycles of 94° C. for 30 seconds, 66.3° C. for 30 seconds and72° C. for 30 seconds, followed by 1 cycle at 72° C. for 5 minutes.About 10 μl of the PCR reaction product was subjected to standardAgarose gel electrophoresis using a 4% agarose gel. The correctpredicted DNA fragment size was observed in lymph node, prostate,thyroid, HPV (prostate epithelia), HPVS (prostate epithelia, selected),lung tumor, uterus tumor reactions, along with the genomic DNA reaction.One of the primers can anneal to genomic or to the zcytor17 short-formsoluble receptor (SEQ ID NO:21), suggesting that the expression patternseen may be that of this alternative form of zcytor17.

The DNA fragment for prostate tissue (2 samples), HPV (prostateepithelia), HPVS (prostate epithelia, selected), and genomic wereexcised and purified using a Gel Extraction Kit (Qiagen, Chatsworth,Calif.) according to manufacturer's instructions. Fragments wereconfirmed by sequencing to show that they were indeed zcytor17. TABLE 5Tissue/Cell line #samples Tissue/Cell line #samples Adrenal gland 1 BoneMarrow 3 Bladder 1 Fetal brain 3 Bone Marrow 1 Islet 2 Brain 1 Prostate3 Cervix 1 RPMI #1788 (ATCC # 2 CCL-156) Colon 1 Testis 4 Fetal brain 1Thyroid 2 Fetal heart 1 WI38 (ATCC # CCL-75 2 Fetal kidney 1 ARIP (ATCC# 1 CRL-1674 - rat) Fetal liver 1 HaCat - human keratinocytes 1 Fetallung 1 HPV (ATCC # CRL-2221) 1 Fetal muscle 1 Adrenal gland 1 Fetal skin1 Prostate SM 2 Heart 2 CD3+ selected PBMC's 1 Ionomycin + PMAstimulated K562 (ATCC # 1 HPVS (ATCC # CRL- 1 CCL-243) 2221) - selectedKidney 1 Heart 1 Liver 1 Pituitary 1 Lung 1 Placenta 2 Lymph node 1Salivary gland 1 Melanoma 1 HL60 (ATCC # CCL-240) 3 Pancreas 1 Platelet1 Pituitary 1 HBL-100 1 Placenta 1 Renal mesangial 1 Prostate 1 T-cell 1Rectum 1 Neutrophil 1 Salivary Gland 1 MPC 1 Skeletal muscle 1 Hut-102(ATCC # TIB-162) 1 Small intestine 1 Endothelial 1 Spinal cord 1 HepG2(ATCC # HB-8065) 1 Spleen 1 Fibroblast 1 Stomach 1 E. Histo 1 Testis 2Thymus 1 Thyroid 1 Trachea 1 Uterus 1 Esophagus tumor 1 Gastric tumor 1Kidney tumor 1 Liver tumor 1 Lung tumor 1 Ovarian tumor 1 Rectal tumor 1Uterus tumor 1B. Expression Analysis of Zcytor17 by PCR and Northern

Annotation of the cell types and growth conditions that affectexpression of the receptor is a useful means of elucidating its functionand predicting a source of ligand. To that end we surveyed a widevariety of tissue and cell types by PCR. The thermostable polymeraseAdvantage II™ (Clontech, La Jolla, Calif.) was used with theoligonucleotide primers ZC29,180 (SEQ ID NO:73) and ZC29,179 (SEQ IDNO:74) and 1-10 ng of the various cDNA templates listed below for 30amplification cycles of (94° C., 30 sec.; 66° C., 20 sec.; 68° C. 1 min.30 sec.). Following this, 20% of each reaction was run out on 0.8%agarose, TAE/ethidium bromide gels and visualized with UV light. Sampleswere then scored on the basis of band intensity. See Table 6 below.TABLE 6 Cells and Conditions Score 0-5 Hel stimulated with PMA 0 U937 3MCF-7 0 HuH7 1 Human follicle 0 HT-29 0 HEPG2 0 HepG2 stimulated withIL6 0 Human dermal endothelial 0 Human venous endothelial 0 Human CD4+ 0BEWO 0 Human CD19+ 1 Human PBMC stimulated with PHA, PMA, Ionomycin, 0IL2, IL4, TNFα 24 hours Human PBMC stimulated with LPS, PWM, IFNγ, TNFα,0 24 hours Human PBMC all of the above conditions for 48 hours 4 HUVECp.2 4 RPMI1788 0 TF1 0 Monkey spleen T cells stimulated with PMA,Ionomycin 0 Human prostate epithelia HPV transformed 5 Human tonsils,inflamed 0 HACAT 0 Human chondrocyte 1 Human synoviacyte 1 THP1 5 REH 0

Of the strong positive PCR signals, two were from the human monocytecell lines U937 and THP1.

These two cell lines along with a prostate epithelia line were selectedfor further analysis by Northern blot. Previous attempts at visualizinga transcript by northern analysis using mRNA from various tissuesyielded weak and diffuse signals in the suprisingly large size range of7-10 kb making this data difficult to interpret. A denaturingformaldehyde/MOPS/0.8% agarose gel was prepared (RNA Methodologies,Farrell, R E Academic Press) and 2 μg of polyA+ mRNA was run for eachsample along side an RNA ladder (Life Technologies, Bethesda, Md.). Thegel was then transferred to Hybond nylon (Amersham, Buckinghamshire,UK), UV crosslinked, and hybridized in ExpressHyb solution (Clontech,LaJolla, Calif.) at 68° C. overnight using a probe to human zcytor17generated by PCR with the oligos ZC28,575 (SEQ ID NO:23), and ZC27,899(SEQ ID NO:24) and labeled with a Megaprime ³²P kit (Amersham). Thenorthern blot was subsequently washed with 0.2×SSC+0.1% SDS at 65 C for15 minutes and exposed to film for 7 days with intensifying screens. Aprominent 8 kb band was seen in both the prostate epithelia and U937lanes while a fainter band was present in the THP1 lane.

To optimize the cDNA used as a hybridization probe, four differentregions of the full-length human zcytoR17 sequence were amplified byPCR, labeled and hybridized as described above to southern blotscontaining genomic and amplified cDNA library DNA. The four probes,herein designated probes A-D, were amplified using the following primerpairs: (A) ZC28,575 (SEQ ID NO:23), ZC27,899 (SEQ ID NO:24); (B)ZC27,895 (SEQ ID NO:64), ZC28,917 (SEQ ID NO:73); (C) ZC28,916 (SEQ IDNO:75), ZC28,918 (SEQ ID NO:76); and (D) ZC28,916 (SEQ ID NO:75),ZC29,122 (SEQ ID NO:65). Human genomic DNA along with amplified cDNAlibraries demonstrated to contain zcytor17 by PCR were digested withEcoR1 and Xho1 to liberate inserts and run out on duplicate TAE/0.8%agarose gels, denatured with 0.5M NaOH, 1.5 M NaCl, blotted to Hybond,UV crosslinked and each hybridized with a distinct probe. Probe B wasfound to have the least nonspecific binding and strongest signal. Thus,Probe B was used for all subsequent hybridizations.

Given that the THP1 cells are an excellent model of circulatingmonocytes and expressed zcytor17 at low levels we treated them with avariety of compounds in an effort to increase expression of zcytor17.The cells were grown to a density of 2e5/ml, washed and resuspended invarious stimulating media, grown for four or thirty hours, and harvestedfor RNA preparations. Each media was supplemented with one of thefollowing drugs or pairs of cytokines: LPS 2 ug/ml (Sigma Chemicals, StLouis Mo.), hTNFα2 ng/ml (R&D Systems, Minneapolis, Minn.), hGMCSF 2ng/ml (R&D Systems,Minneapolis, Minn.), hIFNγ50 ng/ml (R&D Systems,Minneapolis, Minn.), hMCSF 1 ng/ml (R&D Systems,Minneapolis, Minn.),hIL6 1 ng/ml (R&D Systems,Minneapolis, Minn.), hIL1β 2 ng/ml (R&DSystems, Minneapolis, Minn.), hIFNγ 50 ng/ml+hIL4 0.5 ng/ml (R&DSystems, Minneapolis, Minn.), hIFNγ 50 ng/ml+hIL10 1 ng/ml (R&D Systems,Minneapolis, Minn.), PMA 10 ng/ml (Calbiochem, San Diego, Calif.) and anuntreated control. At the end of the culture period Total RNA wasprepared using an RNAeasy Midi-kit (Qiagen, Valencia, Calif.). Poly A+RNA was selected from the total RNA using an MPG kit (CPG, Lincoln Park,N.J.). 2 ug of polyA+ RNA from each condition was run onformaldehyde/MOPS/agarose gels, transferred to nylon and, UV crosslinkedas described above. These northern blots were then hybridized, as above,to probe B at 68° C. overnight, washed at high stringency with 0.2×SSC,0.1% SDS at 65 C, exposed to film overnight then exposed to phosphorscreens for signal quantitation (see FIG. 2). A dominant 8 kb mRNA aswell a relatively weaker 2.8 kb band were seen in all lanes. A 20-foldincrease in zcytor17 mRNA was seen in RNA from cells treated with hIFNγfor 30 hours, this effect was slightly muted with simultaneous treatmentwith IL4. Minor 3 fold increases in mRNA were seen in RNA from cellstreated with LPS, TNFα and GM-CSF while MCSF, IL6, and IL1β had noeffect on zcytor17 mRNA levels. Taken together this data suggests a rolefor the zcytor17 receptor and its ligand in monocyte macrophage biologyand by extension any number of disease processes in which these cellparticipate.

Example 4 PCR-Based Chromosomal Mapping of the Zcytor17 Gene

Zcytor17 was mapped to chromosome 5 using the commercially available“GeneBridge 4 Radiation Hybrid (RH) Mapping Panel” (Research Genetics,Inc., Huntsville, Ala.). The GeneBridge 4 RH panel contains DNA fromeach of 93 radiation hybrid clones, plus two control DNAs (the HFL donorand the A23 recipient). A publicly available WWW server(http://www-genome.wi.mit.edu/cgi-bin/contig/rhmapper.pl) allows mappingrelative to the Whitehead Institute/MIT Center for Genome Research'sradiation hybrid map of the human genome (the “WICGR” radiation hybridmap) which was constructed with the GeneBridge 4 RH panel.

For the mapping of Zcytor17 with the GeneBridge 4 RH panel, 20 μlreactions were set up in a 96-well microtiter plate compatible for PCR(Stratagene, La Jolla, Calif.) and used in a “RoboCycler Gradient 96”thermal cycler (Stratagene). Each of the 95 PCR reactions consisted of 2μl 10× KlenTaq PCR reaction buffer (CLONTECH Laboratories, Inc., PaloAlto, Calif.), 1.6 μl dNTPs mix (2.5 mM each, PERKIN-ELMER, Foster City,Calif,), 1 μl sense primer, ZC27,895 (SEQ ID NO: 14), 1 μl antisenseprimer, ZC27,899 (SEQ ID NO:24), 2 μl “RediLoad” (Research Genetics,Inc., Huntsville, Ala.), 0.4 μl 50× Advantage KlenTaq Polymerase Mix(Clontech Laboratories, Inc.), 25 ng of DNA from an individual hybridclone or control and distilled water for a total volume of 20 μl. Thereactions were overlaid with an equal amount of mineral oil and sealed.The PCR cycler conditions were as follows: an initial 1 cycle 5 minutedenaturation at 94° C., 35 cycles of a 45 seconds denaturation at 94°C., 45 seconds annealing at 54° C. and 1 minute AND 15 seconds extensionat 72° C., followed by a final 1 cycle extension of 7 minutes at 72° C.The reactions were separated by electrophoresis on a 2% agarose gel (EMScience, Gibbstown, N.J.) and visualized by staining with ethidiumbromide.

The results showed that Zcytor17 maps 6.72 cR_(—)3000 distal from theframework marker AFM183YB8 on the chromosome 5 WICGR radiation hybridmap. The use of surrounding genes/markers positions Zcytor17 in the 5q11chromosomal region.

Example 5 Construction of MPL-zcytor17 Polypeptide Chimera: MPLExtracellular and TM Domain Fused to the Zcytor17 IntracellularSignaling Domain

The 5′ extracellular domain of the murine MPL receptor was isolated froma plasmid containing the murine MPL receptor (PHZ1/MPL plasmid) bydigestion with EcoRI and BamHI generating a 1164 bp fragment. Thedigestion was run on a 1% agarose gel and the fragment was isolatedusing the Qiaquick gel extraction kit (Qiagen) as per manufacturer'sinstructions. The rest of the MPL extracellular domain and transmembranedomain were generated using PCR with primers ZC6,673 (SEQ ID NO:58) andZC29,082 (SEQ ID NO:59). The reaction conditions were as follows: 15cycles at 94° C. for 1 min., 55° C. for 1 min., 72° C. for 2 min.;followed by 72° C. for 7 min.; then a 4° C. soak. The PCR product wasrun on a 1% agarose gel and the approximately 400 bp MPL receptorfragment was isolated using Qiaquick™ gel extraction kit (Qiagen) as permanufacturer's instructions.

The intracellular domain of human zcytor17 was isolated from a plasmidcontaining zcytor17 receptor cDNA (#23/pCAP) using PCR with primersZC29,083 (SEQ ID NO:60) and ZC29,145 (SEQ ID NO:61). The polynucleotidesequence corresponds to the zcytor17 receptor coding sequence is shownin SEQ ID NO:54. The reaction conditions were as per above. The PCRproduct was run on a 1% agarose gel and the approximately 320 bpzcytor17 fragment isolated using Qiaquick gel extraction kit as permanufacturer's instructions.

Each of the isolated PCR fragments described above were mixed at a 1:1volumetric ratio and used in a PCR reaction using ZC6673 (SEQ ID NO:58)and ZC29145 (SEQ ID NO:61) to create all but the 5′ MPL portion of theMPL-zcytor17 chimera. The reaction conditions were as follows: 15 cyclesat 94° C. for 1 min., 55° C. for 1 min., 72° C. for 2 min.; followed by72° C. for 7 min.; then a 4° C. soak. The entire PCR product was run ona 1% agarose gel and the approximately 700 bp MPL-zcytor17 chimerafragment isolated using Qiaquick gel extraction kit (Qiagen) as permanufacturer's instructions. The MPL-zcytor17 chimera fragment wasdigested with BamHI (BRL) and XbaI (Boerhinger Mannheim) as permanufacturer's instructions. The entire digest was run on a 1% agarosegel and the cleaved MPL-zcytor17 chimera isolated using Qiaquick™ gelextraction kit (Qiagen) as per manufacturer's instructions. Theresultant cleaved MPL-zvytor17 chimera plus 5′ MPL EcoRI/BamHI fragmentdescribed above were inserted into an expression vector to generate thefull MPL-zcytor17 chimeric receptor as described below.

Recipient expression vector pZP-7 was digested with EcoRI (BRL) and XbaI(BRL) as per manufacturer's instructions, and gel purified as describedabove. This vector fragment was combined with the EcoRI and XbaI cleavedMPL-zcytor17 PCR chimera isolated above and the EcoRI and BamHI 5′ MPLfragment isolated above in a ligation reaction. The ligation was runusing T4 Ligase (Epicentre Technologies), at room temperature for 1 houras per manufacturer's instructions. A sample of the ligation waselectroporated into DH10B ElectroMAX™ electrocompetent E. coli cells (25μF, 200Ω, 1.8V). Transformants were plated on LB+Ampicillin plates andsingle colonies screened by miniprep (Qiagen) and digestion with EcoRIto check for the MPL-zcytor17 chimera. EcoRI digestion of correct clonesyield about a 2 kb fragment. Confirmation of the MPL-zcytor17 chimerasequence was made by sequence analyses. The insert was approximately 3.1kb, and was full-length.

Example 6 MPL-zcytor17 Chimera Based Proliferation in BAF3 Assay UsingAlamar Blue

A. Construction of BaF3 Cells Expressing MPL-zcytor17 Chimera

BaF3, an interleukin-3 (IL-3) dependent pre-lymphoid cell line derivedfrom murine bone marrow (Palacios and Steinmetz, Cell 41: 727-734, 1985;Mathey-Prevot et al., Mol. Cell. Biol. 6: 4133-4135, 1986), wasmaintained in complete media (RPMI medium (JRH Bioscience Inc., Lenexa,Kans.) supplemented with 10% heat-inactivated fetal calf serum, 1 ng/mlmurine IL-3 (mIL-3) (R & D, Minneapolis, Minn.), 2 mM L-glutaMax-™(Gibco BRL), 1 mM Sodium Pyruvate (Gibco BRL), and PSN antibiotics(GIBCO BRL)). Prior to electroporation, pZP-7/MPL-zcytor17 plasmid DNA(Example 5) was prepared and purified using a Qiagen Maxi Prep kit(Qiagen) as per manufacturer's instructions. BaF3 cells forelectroporation were washed twice in RPMI media and then resuspended inRPMI media at a cell density of 10⁷ cells/ml. One ml of resuspended BaF3cells was mixed with 30 μg of the pZP-7/MPL-zcytor17 plasmid DNA andtransferred to separate disposable electroporation chambers (GIBCO BRL).At room temperature cells were given 5×.1 msec shocks at 800 voltsfollowed by 5×2 ms shocks at 600 volts delivered by an electroporationapparatus (Cyto-Pulse). The electroporated cells were transferred to 50ml of complete media and placed in an incubator for 15-24 hours (37° C.,5% CO₂). Then Geneticin™ (Gibco) selection (1 mg/ml G418) was added tothe cells in a T-162 flask to isolate the G418-resistant pool. Pools ofthe transfected BaF3 cells, hereinafter called BaF3/MPL-zcytor17 cells,were assayed for signaling capability as described below.

B. Testing the Signaling Capability of the BaF3/MPL-zcytor17 Cells Usingan Alamar Blue Proliferation Assay

BaF3/MPL-zcytor17 cells were spun down and washed in the complete media,described above, but without mIL-3 (hereinafter referred to as “mLH-3free media”). The cells were spun and washed 3 times to ensure theremoval of the mIL-3. Cells were then counted in a hemacytometer. Cellswere plated in a 96-well format at 5000 cells per well in a volume of100 μl per well using the mIL-3 free media.

Proliferation of the BaF3/MPL-zcytor17 cells was assessed using murinethrombopoietin (mTPO) diluted with mIL-3 free media to 200 ng/ml, 100ng/ml, 50 ng/ml, 25 ng/ml, 12.5 ng/ml, 6.25 ng/ml, 3.1 ng/ml, 1.5 ng/mlconcentrations. 100 μl of the diluted mTPO was added to theBaF3/MPL-zcytor17 cells. The total assay volume is 200 μl. Negativecontrols were run in parallel using mIL-3 free media only, without theaddition of mTPO. The assay plates were incubated at 37° C., 5% CO₂ for3 days at which time Alamar Blue (Accumed, Chicago, Ill.) was added at20 μl/well. Alamar Blue gives a fluorometric readout based on themetabolic activity of cells, and is thus a direct measurement of cellproliferation in comparison to a negative control. Plates were againincubated at 37° C., 5% CO₂ for 24 hours. Plates were read on the Fmax™plate reader (Molecular Devices Sunnyvale, Calif.) using the SoftMax™Pro program, at wavelengths 544 (Excitation) and 590 (Emission).

Results confirmed the signaling capability of the intracellular portionof the zcytor17 receptor, as the thrombopoietin induced proliferation atapproximately 9-13 fold over background at mTPO concentrations of 50ng/ml and greater.

Example 7 Construction of Zcytor17-mpl Polypeptide Chimera: Zcytor17Extracellular Domain Fused to the Mpl Intracellular Signaling Domain andTM Domain

The extracellular domains of the zcytor17 receptor are isolated from aplasmid containing the zcytor17 receptor using PCR with primers designedto amplify the extracellular domain or portion thereof of zcytor17 shownin SEQ ID NO:1, SEQ ID NO:45, SEQ ID NO:17 or SEQ ID NO:21 orcorresponding region of SEQ ID NO:53 or SEQ ID NO:56. Preferred reactionconditions are as follows: 95° C. for 1 min.; 35 cycles at 95° C. for 1min., 45° C. for 1 min., 72° C. for 2 min.; followed by 72° C. at 10min.; then a 10° C. soak. The PCR product is run on a 1% low meltingpoint agarose (Boerhinger Mannheim, Indianapolis, Ind.) and the zcytor17receptor fragment isolated using Qiaquick™ gel extraction kit (Qiagen)as per manufacturer's instructions.

The intracellular and transmembrane domains of MPL are isolated from aplasmid containing MPL receptor cDNA (PHZ1/MPL plasmid) (Example 5)using PCR with primers spanning the 3′ end of the zcytor17 extracellulardomain and the 5′ end of the MPL intracellular and transmembrane domainsand ZC17,206 (SEQ ID NO:33). Preferred reaction conditions are run asper above. The PCR product is run on a 1% low melting point agarose(Boerhinger Mannheim) and the approximately 450 bp MPL fragment isolatedusing Qiaquick gel extraction kit (Qiagen) as per manufacturer'sinstructions.

Each of the isolated fragments described above are mixed at a 1:1volumetric ratio and used in a PCR reaction using the 5′ primer used toamplify the extracellular domain of zcytor17 and ZC17,206 (SEQ ID NO:33)to create a Zcytor17-mpl chimera. Preferred reaction conditions are asfollows: 95° C. for 1 min.; 35 cycles at 95° C. for 1 min., 55° C. for 1min., 72° C. for 2 min.; followed by 72° C. at 10 min.; then a 10° C.soak. The entire PCR product is run on a 1% low melting point agarose(Boehringer Mannheim) and an approximately 1.2 kb Zcytor17-mpl chimerafragment isolated using Qiaquick gel extraction kit (Qiagen) as permanufacturer's instructions. The Zcytor17-mpl chimera fragment isdigested with, e.g., EcoRI (BRL) and XbaI (Boerhinger Mannheim) as permanufacturer's instructions. The entire digest is run on a 1% lowmelting point agarose (Boehringer Mannheim) and the cleaved Zcytor17-mplchimera isolated using Qiaquick™ gel extraction kit (Qiagen) as permanufacturer's instructions. The resultant cleaved Zcytor17-mpl chimerais inserted into an expression vector as described below.

Recipient expression vector pZP-5Z is digested with EcoRI (BRL) andHindIII (BRL) as per manufacturer's instructions, and gel purified asdescribed above. This vector fragment is combined with the EcoRI andXbaI cleaved Zcytor17-mpl chimera isolated above and a XbaI/HindIIIlinker fragment in a ligation reaction. The ligation is run using T4Ligase (BRL), at 15° C. overnight. A sample of the ligation iselectroporated in to DH10B ElectroMAX™ electrocompetent E. coli cells(25 μF, 200Ω, 2.3V). Transformants are plated on LB+Ampicillin platesand single colonies screened by PCR to check for the Zcytor17-mplchimera using a zcytor17 extracellular domain primer and and ZC 17,206(SEQ ID NO:25) using the PCR conditions as described above. Confirmationof the Zcytor17-mpl chimera sequence is made by sequence analyses.

Example 8 Construction of Expression Vector Expressing Full-lengthZcytor17: pZp7pX/Zcytor17

A. Cloning of Full Length Zcytor17 cDNA for Expression:

To obtain a full-length cDNA, 5′ and 3′ PCR products were isolated andjoined using an internal PstI site. The PCR primers were designed usingthe nucleotide sequence SEQ ID NO:53 and include BamHI and Xho Irestriction sites for cloning purposes.

A 5′ PCR product was generated using a WI-38 cDNA library as a templateand oligonucleotides ZC 29,359 (SEQ ID NO:62) and ZC 27,899 (SEQ IDNO:63) as primers. WI-38 is an in-house cDNA library generated from ahuman embryonics lung cell line (ATCC CRL-2221). This 5′ PCR reactionwas run as follows: 30 cycles at 94° C. for 1 minute, 65° C. for 1minute, 72° C. for 2 minutes, then 72° C for 7 minutes; 10° C. soak. ThePCR reaction used approximately 3 ug of plasmid prepared from the cDNAlibrary, 20 pmoles of each oligonucleotide, and five units of PWO DNApolymerase (Roche). About 90% of the 5′ PCR product was ethanolprecipitated, digested with BamHI and PstI and gel purified on a 1.0%agarose gel. The approximately 600 bp band was excised and used forligation to the cloning vector pUC18 digested with BamHI and PstI. Theresulting transformants were sequenced to confirm the zcytor17 cDNAsequence. For one of these transformants, plasmid DNA was prepared anddigested with BamHI and PstI. The resulting approximately 600 bp bandwas gel purified and used for a ligation below to form a full-lengthcDNA.

A 3′ PCR product was generated using a human testes in-house cDNAlibrary as a template and oligonucleotides ZC 27,895 (SEQ ID NO:64) andZC 29,122 (SEQ ID NO:65) as primers. This 3′ PCR reaction was run asfollows: 30 cycles at 94° C. for 45 seconds, 65° C. for 45 seconds, 72°C. for 2 minutes, then 72° C. for 7 minutes; 10° C. soak. The entire 3′PCR reaction was gel purified on a 1.0% agarose gel and the major 1500bp band excised. This band was cloned into the PCR Blunt II TOPO vectorusing the Zeroblunt TOPO kit (Invitrogen). The resulting transformantswere sequenced to confirm the zcytor17 cDNA sequence. For one of thesetransformants, plasmid DNA was prepared and digested with PstI and XhoI.The resulting approximately 1500 bp band was gel purified. A three-partligation was performed with the 5′ BamHI to Pst I fragment above, the 3′PstI to XhoI fragment, and the expression vector pZp7pX digested withBamHI and XhoI. This generated a pZp7pX plasmid containing a full-lengthcDNA for zcytor17 (SEQ ID NO:53), designated pZp7p/zcytor17. The fulllength zcytor17 cDNA in pZp7p/zcytor17 has a silent mutations thatchange the T to G at position 1888 of SEQ ID NO:53 (encoding a Glyresidue at residue 464 of SEQ ID NO:54). As this mutation is silent, thezcytor17 cDNA in pZp7p/zcytor17 encodes the polyepptide as shown in SEQID NO:54. Plasmid pZp7pX is a mammalian expression vector containing anexpression cassette having the CMV promoter, intron A, multiplerestriction sites for insertion of coding sequences, and a human growthhormone terminator. The plasmid also has an E. coli origin ofreplication, a mammalian selectable marker expression unit having anSV40 promoter, enhancer and origin of replication, a puromycinresistance gene and the SV40 terminator.

Example 9 Construction of Cells to Assess Zcytor17 Based Proliferationin BAF3 Assay Using Alamar Blue

A. Construction of BaF3 Cells Expressing Zcytor17-MPL Receptor

BaF3 cells expressing the Zcytor17-MPL receptor are constructed as perExample 6A, using 30 μg of the zcytor17 expression vector, described inExample 7. The BaF3 cells expressing the pZP-5Z/zcytor17 receptorplasmid are designated as BaF3/Zcytor17-mpl. These cells are used toscreen for a zcytor17 activity as described below in Examples 10 and 18.

B. Construction of BaF3 Cells Expressing zcytor17 Receptor

BaF3 cells expressing the full-length zcytor17 receptor are constructedas per Example 6A, using 30 μg of the zcytor17 expression vector,described in Example 8. The BaF3 cells expressing the pZp7p/zcytor17receptor plasmid are designated as BaF3/zcytor17. These cells are usedto screen for a zcytor17 activity as described below in Examples 10 and18.

Example 10 Screening for zcytor17 Activity Using BaF3/zcytor17-MPL Cellsand Baf3/Zcytor17 Cells Using an Alamar Blue Proliferation Assay

Baf3/zcytor17-mpl chimera cells and Baf3/zcytor17 cells (Example 9) arespun down and washed independently in mIL-3 free media (Example 6). Thecells are spun and washed 3 times to ensure the removal of the mIL-3.Cells are then counted in a hemacytometer. Cells are plated in a 96-wellformat at 5000 cells per well in a volume of 100 μl per well using themIL-3 free media.

To try and identify a source for the zcytor17 ligand, approximately 124conditioned media and samples from a variety of cell lines and tissuesare screened. 100 μl of each conditioned media sample is added to theBaF3/MPL-zcytor17 chimera cells as well as the Baf3/zcytor17 cells. Thetotal assay volume is 200 μl. All known cytokines are also screened at aconcentration of about 100 pg/ml-250 ng/ml on both cell lines. Negativecontrols are run in parallel using mIL-3 free media only. Mouse IL-3 ata concentration of 250 pg/ml is used as a positive control. The assayplates are incubated at 37° C., 5% CO₂ for 3 days at which time AlamarBlue (Accumed, Chicago, Ill.) is added at 20 μl/well. Alamar Blue givesa fluorometric readout based on number of live cells, and is thus adirect measurement of cell proliferation in comparison to a negativecontrol. Plates are again incubated at 37° C., 5% CO₂ for 24 hours.Plates are read on the Fmax™ plate reader (Molecular Devices Sunnyvale,Calif.) using the SoftMax™ Pro program, at wavelengths 544 (Excitation)and 590 (Emission).

Results that show proliferation of on either the Baf3/zcytor17-mplchimera cell line or the Baf3/zcytor17 cell line in response toconditioned media samples or the known ligands identify a source for theligand, and suggest that the zcytor17 receptor may signal as ahomodimer, or heterodimerize or multimerize with a receptor present inthe BaF3 cells. If no signal is present, the actual receptor-signalingcomplex may heterodimerize or multimerize with another receptor subunitnot present in BaF3 cells. See example 18 and Example9 below.

Example 11 Construction of Mammalian Expression Vectors That ExpressZcytor17 Soluble Receptors: Zcytor17CEE, Zcytor17CFLG, Zcytor17CHIS andZcytor17-Fc4

A. Construction of Zcytor17 Mammalian Expression Vector ContainingZcytor17CEE, Zcytor17CFLG and Zcytor17CHIS

An expression vector was prepared for the expression of the soluble,extracellular domain of the zcytor17 polypeptide, pZp9zcytor17CEE, wherethe construct is designed to express a zcytor17 polypeptide comprised ofthe predicted initiating methionine and truncated adjacent to thepredicted transmembrane domain, and with a C-terminal GLU-GLU tag (SEQID NO:34).

An approximately 1500 bp PCR product was generated using ZC29,451 (SEQID NO:66) and ZC29,124 (SEQ ID NO:67) as PCR primers to add EcoRI andBamHI restriction sites. A human HPVS in-house cDNA library was used asa template and PCR amplification was performed as follows: 30 cycles at94° C. for 1 minute, 65° C. for 1 minute, 72° C. for 1.5 minutes, then72° C. for 7 minutes; 10° C. soak. The PCR reaction was ethanolprecipitated and digested with EcoRI and BamHI restriction enzymes. Thedigested PCR product was gel purified on a 1.0% agarose gel and theapproximately 1500 bp band excised. This band was then re-amplifiedusing identical primers with the following cycling: 30 cycles at 94° C.for 1 minute, 65° C. for 1 minute, 72° C. for 3 minutes, then 72° C. for7 minutes; 10° C. soak. The PCR reaction was ethanol precipitated anddigested with EcoRI and BamHI restriction enzymes. The digested PCRproduct was gel purified on a 1.0% agarose gel and the approximately1500 bp band excised. The excised DNA was subcloned into plasmid CEEpZp9that had been cut with EcoRI and BamHI, to generate plasmid with aGLU-GLU C-terminally tagged soluble receptor for zcytor17,zcytor17CEEpZp9. The extracellular domain in the zcytor17CEE cDNA inzcytor17CEEpZp9 has a silent mutation that changes the T to C atposition 1705 of SEQ ID NO:53 (encoding a Pro residue at residue 403 ofSEQ ID NO:54). As this mutation is silent, the zcytor17 cDNA inzcytor17CEEpZp9 encodes the polyepptide as shown in SEQ ID NO:54.Moreover, because of the construct used, a Gly-Ser residue pair isinserted C-terminal to the end of the soluble, extracellular domain ofzcytor17 and prior to the C-terminal Glu-Glu Tag (SEQ ID NO:34). Assuch, the tag at the C-terminus of the zcytor17 extracellular domain,was a modified Glu-Glu tag as shown in (SEQ ID NO:91). Plasmid CEEpZp9is a mammalian expression vector containing an expression cassettehaving the mouse metallothionein-1 promoter, multiple restriction sitesfor insertion of coding sequences, and a human growth hormoneterminator. The plasmid also has an E. coli origin of replication, amammalian selectable marker expression unit having an SV40 promoter,enhancer and origin of replication, a DHFR gene and the SV40 terminator.Using standard molecular biological techniques zcytor17CEEpZp9 waselectroporated into DH10B competent cells (GIBCO BRL, Gaithersburg, Md.)according to manufacturer's direction and plated onto LB platescontaining 100 μg/ml ampicillin, and incubated overnight. Colonies werescreened by restriction analysis, or PCR from DNA prepared fromindividual colonies. The insert sequence of positive clones was verifiedby sequence analysis. A large scale plasmid preparation was done using aQIAGEN® Maxi prep kit (Qiagen) according to manufacturer's instructions.

The same process is used to prepare the zcytor17 soluble receptors witha C-terminal his tag, composed of 6 His residues in a row; and aC-terminal FLAG® tag (SEQ ID NO:35), zcytor17CFLAG. To construct theseconstructs, the aforementioned vector has either the HIS or the FLAG®tag in place of the glu-glu tag (SEQ ID NO:34).

B. Mammalian Expression Construction of Soluble Human Zcytor17 Receptor:Zcytor17-Fc4

An expression vector, pEZE-2 hzcytor17/Fc4, was prepared to express aC-terminally Fc4 tagged soluble version of hzcytor17 (humanzcytor17-Fc4) in PF CHO cells. PF CHO cells are an in house CHO cellline adapted for growth in protein-free medium (ExCell 325 PF medium;JRH Biosciences). The in house CHO cell line was originally derived fromCHO DG44 cells (G. Urlaub, J. Mitchell, E. Kas, L. A. Chasin, V. L.Funanage, T. T. Myoda and J. L. Hamlin, “The Effect Of Gamma Rays at theDihydrofolate Reductase Locus: Deletions and Inversions,” Somatic Celland Molec. Genet., 12: 555-566 (1986). A fragment of zcytor17 cDNA thatincludes the polynucleotide sequence from extracellular domain of thezcytor17 receptor was fused in frame to the Fc4 polynucleotide sequence(SEQ ID NO:36) to generate a zcytor17-Fc4 fusion (SEQ ID NO:68 and SEQID NO:69). The pEZE-2 vector is a mammalian expression vector thatcontains the Fc4 polynucleotide sequence and a cloning site that allowsrapid construction of C-terminal Fc4 fusions using standard molecularbiology techniques.

A 1566 base pair fragment was generated by PCR, containing theextracellular domain of human zcytor17 and the first two amino acids ofFc4 (Glu and Pro) with FseI and BglII sites coded on the 5′ and 3′ ends,respectively. This PCR fragment was generated using primers ZC29,157(SEQ ID NO:70) and ZC29,150 (SEQ ID NO:71) by amplification from aplasmid containing the extracellular domain of human zcytor17(pZp9zcytor17CEE) (Example 11A). The PCR reaction conditions were asfollows: 25 cycles of 94° C. for 1 minute, 60° C. for 1 minute, and 72°C. for 2 minutes; 1 cycle at 72° C. for 10 minute; followed by a 4° C.soak. The fragment was digested with FseI and BglII restrictionendonucleases and subsequently purified by 1% gel electrophoresis andband purification using QiaQuick gel extraction kit (Qiagen). Theresulting purified DNA was ligated for 5 hours at room temperature intoa pEZE-2 vector previously digested with FseI and BglII containing Fc43′ of the FseI and BglII sites.

Two μl of the ligation mix was electroporated in 37 μl DH10Belectrocompetent E. coli (Gibco) according to the manufacturer'sdirections. The transformed cells were diluted in 400 μl of LB media andplated onto LB plates containing 100 μg/ml ampicillin. Clones wereanalyzed by restriction digests and positive clones were sent for DNAsequencing to confirm the sequence of the fusion construct. 1 μl of apositive clone was transformed into 37 μl of DH10B electrocompetent E.coli and streaked on a LB/amp plate. A single colony was picked fromthis streaked plate to start a 250 ml LB/amp culture that was then grownovernight at 37° C. with shaking at 250 rpm. This culture was used togenerate 750 μg of purified DNA using a Qiagen plasmid Maxi kit(Qiagen).

Example 12 Transfection And Expression Of Zcytor17 Soluble ReceptorPolypeptides

BHK 570 cells (ATCC No. CRL-10314), DG-44 CHO, or other mammalian cellsare plated at about 1.2×10⁶ cells/well (6-well plate) in 800 μl ofappropriate serum free (SF) media (e.g., DMEM, Gibco/BRL High Glucose)(Gibco BRL, Gaithersburg, Md.). The cells are transfected withexpression plasmids containing zcytor17CEE, zcytor17CFLG, zcytor17CHISor zcytor17-Fc4 (Example 11), using Lipofectin™ (Gibco BRL), in serumfree (SF) media according to manufacturer's instruction. Single clonesexpressing the soluble receptors are isolated, screened and grown up incell culture media, and purified using standard techniques.

A. Mammalian Expression of Soluble Human Zcytor17CEE Receptor

BHK 570 cells (ATCC NO: CRL-10314) were plated in T-75 tissue cultureflasks and allowed to grow to approximately 50 to 70% confluence at 37°C., 5% CO₂, in DMEM/FBS media (DMEM, Gibco/BRL High Glucose, (Gibco BRL,Gaithersburg, Md.), 5% fetal bovine serum, 1 mM L-glutamine (JRHBiosciences, Lenea, Kans.), 1 mM sodium pyruvate (Gibco BRL)). The cellswere then transfected with the plasmid containing zcytor17CEE (Example11A) using Lipofectamine™ (Gibco BRL), in serum free (SF) mediaformulation (DMEM, 10 mg/ml transferrin, 5 mg/ml insulin, 2 mg/mlfetuin, 1% L-glutamine and 1% sodium pyruvate). Ten μg of the plasmidDNA pZp9zcytor17CEE (Example 11A) was diluted into a 15 ml tube to atotal final volume of 500 μl with SF media. 50 μl of Lipofectamine wasmixed with 450 μl of SF medium. The Lipofectamine mix was added to theDNA mix and allowed to incubate approximately 30 minutes at roomtemperature. Four ml of SF media was added to the DNA:Lipofectaminemixture. The cells were rinsed once with 5 ml of SF media, aspirated,and the DNA:Lipofectamine mixture was added. The cells were incubated at37° C. for five hours, and then 5 ml of DMEM/10%FBS media was added. Theflask was incubated at 37° C. overnight after which time the cells weresplit into the selection media (DMEM/FBS media from above with theaddition of 1 μM methotrexate or 10 μM Methotrexate (Sigma Chemical Co.,St. Louis, Mo.) in 150 mm plates at 1:2, 1:10, and 1:50. Approximately10 days post-transfection, one 150 mm plate of 1 μM methotrexateresistant colonies was trypsinized, the cells were pooled, and one-halfof the cells were replated in 10 μM methotrexate; to further amplifyexpression of the zcytor17CEE protein. A conditioned-media sample fromthis pool of amplified cells was tested for expression levels usingSDS-PAGE and Western analysis.

B. Mammalian Expression of Soluble Human Zcytor17-Fc4 Receptor

Twenty μg of pEZE-2hzcytor17Fc4 plasmid DNA (Example 11B) was linearizedby restriction digestion with FspI, a restriction enzyme that cuts oncewithin the pEZE-2 vector and does not disturb genes necessary forexpression. 200 μg of sheared salmon sperm DNA was added as carrier DNAand then the DNA was precipitated by addition of 0.1 volumes of 3MSodium Acetate pH 5.2 and 2.2 volumes ethanol followed by a 15 minuteice incubation and microcentrifugation at 4° C. The resulting DNA pelletwas washed in 70% ethanol and air dried before being resuspended in 100μl PF CHO non-selection growth media (21 g/L PF CHO Ex Cell 325/200 mML-glutamine (Gibco)/100 mM sodium pyruvate (Gibco)/1× HT Supplement(Gibco). Five million PF CHO passage 43 cells were added to the DNA in600 μl of PF CHO non-selection growth media and then electroporated in aGene Pulser II Electroporation system (BioRad) using 1070 μF capacitanceand 380 volts using a 0.4 cm gap Gene Pulser (BioRad) electroporationcuvette. The electroporated cells were allowed to recover for 48 hoursin non-selection growth media before selection in −HT media (21 g/L PFCHO Ex Cell 325/200 mM L-glutamine (Gibco)/100 mM sodium pyruvate(Gibco). Cells were selected for 5 days in −HT media before beingpassaged at 5×10⁵ ml into 50 nm MTX selection. Cells selected at 50 nmMTX were seeded at 6×10⁵ ml in a shake flask to generate conditionedmedia. The resulting 72 hour conditioned media was analyzed by probingwestern blots with an antibody generated against human Ig. The cellsproduced hzcytor17/Fc4 protein at approximately 1 mg/L.

C. Larger-scale Mammalian Expression of Soluble Human Zcytor17-Fc4Rreceptor

Two hundred μg of pEZE-2hzcytor17Fc4 plasmid DNA (Example 11B) waslinearized by restriction digestion with FspI, a restriction enzyme thatcuts once within the pEZE-2 vector and does not disturb genes necessaryfor expression. 200 μg of CHO genomic DNA (prepared in-house) was addedas carrier DNA and then the DNA was precipitated by addition of 0.1volumes of 3M Sodium Acetate pH 5.2 and 2.5 volumes ethanol followed bymicrocentrifugation at Room temperature. Five replicate DNA pellets weremade and transformed. The resulting DNA pellet was washed in 70% ethanoland air dried before being resuspended in 100 μl PF CHO non-selectiongrowth media (21 g/L PF CHO Ex Cell 325/200 mM L-glutamine (Gibco)/100mM sodium pyruvate (Gibco)/1× HT Supplement (Gibco). Ten million PF CHOcells were added to the DNA in 600 μl of PF CHO non-selection growthmedia and then electroporated in a Gene Pulser II Electroporation system(BioRad) using 950 μF capacitance and 300 volts using a 0.4 cm gap GenePulser (BioRad) electroporation cuvette. The electroporated cells werepooled and put directly into selection in −HT media (21 g/L PF CHO ExCell 325/200 mM L-glutamine (Gibco)/100 mM sodium pyruvate (Gibco).Cells were selected for 14 days in −HT media before being passaged at4×10⁵/ml into 50 nm MTX selection. Cells were amplified to 200 nM MTXand then to 1 uM MTX. The −HT, 50 nM, and 1 uM pools were seeded at1×10⁶ c/ml for 48 hours, and the resulting conditioned media wasanalyzed by probing western blots with an antibody generated againsthuman Ig.

C. Transient Mammalian Expression and Purification of Soluble HumanZcytor17-Fc4 Receptor

pEZE-2hzcytor17Fc4 plasmid DNA (Example 11B) was introduced into 40 maxiplates of BHK cells using Lipofectamine (Gibco BRL) as described hereinand in manufacturer's instructions. Cells were allowed to recoverovernight, then were rinsed and refed with serum-free medium (SL7V4,made in-house). After 72 hours, the media was collected and filtered,and cells were refed with serum-free medium. After 72 hours, the mediawas again collected and filtered.

The serum-free conditioned media (2×1.5 L batches) from transientlytransfected BHK cells was pumped over a 1.5 ml Protein A-agarose columnin 20 mM Tris, pH 7.5, 0.5 M NaCl. The column was washed extensivelywith this buffer and then the bound protein was eluted with 1 ml of 0.2M glycine, pH 2.5, 0.5 M NaCl. The eluted protein was collected into 0.1ml of 2 M Tris, pH 8.5.

Aliquots were collected for SDS-polyacrylamide gel electrophoresis andthe bulk zcytor17-Fc was dialyzed overnight against PBS. The solublereceptor was sterile filtered and placed in aliquots at −80° C.

Example 13 Expression of Zcytor17 Soluble Receptor in E. coli

A. Construction of Expression Vector pCZR225 that ExpressesHuzcytor17/MBP-6H Fusion Polypeptide

An expression plasmid containing a polynucleotide encoding a zcytor17soluble receptor fused C-terminally to maltose binding protein (MBP) wasconstructed via homologous recombination. The fusion polypeptidecontains an N-terminal approximately 388 amino acid MBP portion fused toany of the zcytor17 soluble receptors described herein. A fragment ofzcytor17 cDNA (SEQ ID NO:1, SEQ ID NO:45, SEQ ID NO: 17 or SEQ ID NO:21)was isolated using PCR as described herein. Two primers were used in theproduction of the zcytor17 fragment in a standard PCR reaction: (1) onecontaining about 40 bp of the vector flanking sequence and about 25 bpcorresponding to the amino terminus of the zcytor17, and (2) anothercontaining about 40 bp of the 3′ end corresponding to the flankingvector sequence and about 25 bp corresponding to the carboxyl terminusof the zcytor17. Two μl of the 100 μl PCR reaction was run on a 1.0%agarose gel with 1× TBE buffer for analysis, and the expectedapproximately fragment was seen. The remaining PCR reaction was combinedwith the second PCR tube and precipitated with 400 μl of absoluteethanol. The precipitated DNA used for recombining into the Smal cutrecipient vector pTAP170 to produce the construct encoding theMBP-zcytor17 fusion, as described below.

Plasmid pTAP170 was derived from the plasmids pRS316 and pMAL-c2. Theplasmid pRS316 was a Saccharomyces cerevisiae shuttle vector (Hieter P.and Sikorski, R., Genetics 122:19-27, 1989). pMAL-C2 (NEB) was an E.coli expression plasmid. It carries the tac promoter driving MalE (geneencoding MBP) followed by a His tag, a thrombin cleavage site, a cloningsite, and the rrnB terminator. The vector pTAP98 was constructed usingyeast homologous recombination. 100 ng of EcoR1 cut pMAL-c2 wasrecombined with 1 μg Pvu1 cut pRS316, 1 μg linker, and 1 μg Sca1/EcoR1cut pRS316 were combined in a PCR reaction. PCR products wereconcentrated via 100% ethanol precipitation.

Competent yeast cells (S. cerevisiae) were combined with about 10 μl ofa mixture containing approximately 1 μg of the zcytor17 receptor PCRproduct above, and 100 ng of Smal digested pTAP98 vector, andelectroporated using standard methods and plated onto URA-D plates andincubated at 30° C.

After about 48 hours, the Ura+ yeast transformants from a single platewere picked, DNA was isolated, and transformed into electrocompetent E.coli cells (e.g., MC1061, Casadaban et. al. J. Mol. Biol. 138, 179-207),and plated on MM/CA +AMP 100 mg/L plates (Pryor and Leiting, ProteinExpression and Purification 10:309-319, 1997).using standard procedures.Cells were grown in MM/CA with 100 μg/ml Ampicillin for two hours,shaking, at 37° C. 1 ml of the culture was induced with 1 mM IPTG. 2-4hours later the 250 μl of each culture was mixed with 250 μl acid washedglass beads and 250 μl Thorner buffer with 5% βME and dye (8M urea, 100mM Tris pH7.0, 10% glycerol, 2mM EDTA, 5% SDS). Samples were vortexedfor one minute and heated to 65° C. for 10 minutes. 20 μl were loadedper lane on a 4%-12% PAGE gel (NOVEX). Gels were run in 1×MES buffer.The positive clones were designated pCZR225 and subjected to sequenceanalysis.

One microliter of sequencing DNA was used to transform strain BL21. Thecells were electropulsed at 2.0 kV, 25 μF and 400 ohms. Followingelectroporation, 0.6 ml MM/CA with 100 mg/L Ampicillin. Cells were grownin MM/CA and induced with ITPG as described above., The positive cloneswere used to grow up for protein purification of the huzcytor17/MBP-6Hfusion protein using standard techniques.

B. Purification of Huzcytor17/MBP-6H Soluble Receptor from E. coliFermentation

Unless otherwise noted, all operations were carried out at 4° C. Thefollowing procedure was used for purifying huzcytor17/MBP-6H solublereceptor polypeptide. E. coli cells containing the pCZR225 construct andexpressing huzcytor17/MBP-6H soluble receptor (Example 13A) were grownup in SuperBroth II (12 g/L Casien, 24 g/L Yeast Extract, 11.4 g/Ldi-potassium phosphate, 1.7 g/L Mono-potassium phosphate; BectonDickenson, Cockeysville, Md.), and frozen in 0.5% glycerol. Twenty gramsof the frozen cells in SuperBroth II+Glycerol were used to purify theprotein. The frozen cells were thawed and diluted 1:10 in a proteaseinhibitor solution (Extraction buffer) prior to lysing the cells andreleasing the huzcytor17/MBP-6H soluble receptor protein. The dilutedcells contained final concentrations of 20 mM Tris (JT Baker,Philipsburg, N.J.) 100 mM Sodium Chloride (NaCl, Mallinkrodt, Paris,Ky.), 0.5 mM pheynlmethylsulfonyl fluoride (PMSF, Sigma Chemical Co.,St. Louis, Mo.), 2 μg/ml Leupeptin (Fluka, Switzerland), and 2 μg/mlAprotinin (Sigma). A French Press cell breaking system (Constant SystemsLtd., Warwick, UK) with temperature of −7 to −10° C. and 30K PSI wasused to lyse the cells. The diluted cells were checked for breakage byA₆₀₀ readings before and after the French Press. The lysed cells werecentrifuged @ 18,000G for 45 minutes to remove the broken cell debris,and the supernatant used to purify the protein.

A 25 ml column of Amylose resin (New England Biolabs, Beverly, Mass.)(prepared as described below) was poured in a Bio-Rad, 2.5 cm D×10 cm Hglass column. The column was packed and equilibrated by gravity with 10column volumes (CVs) of Amylose Equilibration buffer (20 mM Tris, 100 mMNaCl, pH 8.0). The supernatant was batch loaded to the Amylose resin andwas rocked overnight. The resin was poured back into the column and waswashed with 10 CV's of Amylose Equilibration buffer by gravity. Thecolumn was washed for 10 CVs with Amylose equilibration buffer, theneluted with ˜2 CV of Amylose equilibration buffer +10 mM Maltose (FlukaBiochemical, Switzerland) by gravity. 5 ml fractions were collected overthe entire chromatography and absorbance at 280 and 320 nM were read.The Amylose column was regenerated with 1 CV of distilled H₂O, 5 CVs of0.1% (w/v) SDS (Sigma), 5 CVs of distilled H₂O, and then 5 CVs ofAmylose equilibration buffer.

Fractions of interest were pooled and dialyzed in a Slide-A-Lyzer(Pierce) with 4×4L PBS pH 7.4 (Sigma) to remove low molecular weightcontaminants, buffer exchange and desalt. After the changes of PBS, thematerial harvested represented the purified huzcytor17/MBP-6Hpolypeptide. The purified huzcytor17/MBP-6H polypeptide was analyzed viaSDS-PAGE Coomassie staining and Western blot analyses with theanti-rabbit HRP conjugated antibody (Rockland, Gilbertsville, Pa.). Theconcentration of the huzcytor17/MBP-6H polypeptide was 1.92 mg/ml asdetermined by BCA analysis.

Purified huzcytor17/MBP-6H polypeptide was prepared for injection intorabbits and sent to R & R Research and Development (Stanwood, Wash.) forantibody production. Rabbits were injected to produce antianti-huzcytor17/MBP-6H serum (Example 15, below).

Example 14 Zcytor17 Soluble Receptor Polyclonal Antibodies

Polyclonal antibodies were prepared by immunizing 2 female New Zealandwhite rabbits with the purified huzcytor17/MBP-6H polypeptide (Example13),. The rabbits are each given an initial intraperitoneal (IP)injection of 200 μg of purified protein in Complete Freund's Adjuvant(Pierce, Rockford, Ill.) followed by booster IP injections of 100 ugpurified protein in Incomplete Freund's Adjuvant every three weeks.Seven to ten days after the administration of the third boosterinjection, the animals are bled and the serum is collected. The rabbitsare then boosted and bled every three weeks.

The zcytor17-specific polyclonal antibodies are affinity purified fromthe rabbit serum using an CNBr-SEPHAROSE 4B protein column (PharmaciaLKB) that is prepared using about 10 mg of the purifiedhuzcytor17/MBP-6H polypeptide per gram CNBr-SEPHAROSE, followed by 20×dialysis in PBS overnight. Zcytor17-specific antibodies arecharacterized by an ELISA titer check using 1 ug/ml of the appropriateprotein antigen as an antibody target. The lower limit of detection(LLD) of the rabbit anti-zcytor17 affinity purified antibodies isdetermined using standard methods.

Example 15 Zcytor17 Receptor Monoclonal Antibodies

Zcytor17 soluble receptor Monoclonal antibodies are prepared byimmunizing female BalbC mice with the purified recombinant solublezcytor17 proteins described herein. The mice are each given an initialintraperitoneal (IP) injection of 20 ug of purified protein in CompleteFreund's Adjuvant (Pierce, Rockford, Ill.) followed by booster IPinjections of 10 ug purified protein in Incomplete Freund's Adjuvantevery two weeks. Seven to ten days after the administration of the thirdbooster injection, the animals are bled and the serum is collected, andantibody titer assessed.

Splenocytes are harvested from high-titer mice and fused to murine SP2/0myeloma cells using PEG 1500 (Boerhinger Mannheim, UK) using a 4:1fusion ratio of splenocytes to myeloma cells (Antibodies: A LaboratoryManual, E. Harlow and D. Lane, Cold Spring Harbor Press). Following 10days growth post-fusion, specific antibody-producing hybridomas areidentified by ELISA using purified recombinant zcytor17 soluble receptorprotein (Example 6C) as an antibody target and by FACS using Baf3 cellsexpressing the zcytor17 sequence (Example 8) as an antibody target. Theresulting hybridomas positive by both methods are cloned three times bylimiting dilution.

Example 16 Assessing Zcytor17 Receptor Heterodimerization Using ORIGENAssay

Soluble zcytor17 receptor zcytor17CFLAG (Example 11), or gp130 (Hibi, M.et al., Cell 63:1149-1157, 1990) are biotinylated by reaction with afive-fold molar excess of sulfo-NHS-LC-Biotin (Pierce, Inc., Rockford,Ill.) according to the manufacturer's protocol. Soluble zcytor17receptor and another soluble receptor subunit, for example, solublegp130, LIF, IL-12, WSX-1, IL-7Rα (sIL-7Rα) or IL-2 receptors-γ (sIL-2Rγ)(R&D Systems, Minneapolis, Minn.), or soluble zalpha11 receptor (IL-21R;commonly owned U.S. patent application Ser. No. 09/404,641) are labeledwith a five fold molar excess of Ru-BPY-NHS (Igen, Inc., Gaithersburg,Md.) according to manufacturer's protocol. The biotinylated andRu-BPY-NHS-labeled forms of the soluble zcytor17 receptor can berespectively designated Bio-zcytor17 receptor and Ru-zcytor17; thebiotinylated and Ru-BPY-NHS-labeled forms of the other soluble receptorsubunit can be similarly designated. Assays can be carried out usingconditioned media from cells expressing a ligand that binds zcytor17heterodimeric receptors, or using purified ligands. Preferred ligandsare those that can bind class 1 heterodimeric cytokine receptors suchas, gp130, LIF, IL-12, IL-2, IL-4, IL-7, IL-9, IL-15, zalpha11 Ligand(IL-21) (commonly owned U.S. patent application Ser. No. 09/522,217),TSLP (Levine, SD et al., ibid.; Isaksen, DE et al., ibid.; Ray, R J etal., ibid.; Friend, SL et al., ibid.).

For initial receptor binding characterization a panel of cytokines orconditioned medium are tested to determine whether they can mediatehomodimerization of zcytor17 receptor and if they can mediate theheterodimerization of zcytor17 receptor with the soluble receptorsubunits described above. To do this, 50 μl of conditioned media orTBS-B containing purified cytokine, is combined with 50 μl of TBS-B (20mM Tris, 150 mM NaCl, 1 mg/ml BSA, pH 7.2) containing e.g., 400 ng/ml ofRu-zcytor17 receptor and Bio-zcytor17, or 400 ng/ml of Ru-zcytor17receptor and e.g., Bio-gp130, or 400 ng/ml of e.g., Ru-IL2Rγ andBio-zcytor17. Following incubation for one hour at room temperature, 30μg of streptavidin coated, 2.8 mm magnetic beads (Dynal, Inc., Oslo,Norway) are added and the reaction incubated an additional hour at roomtemperature. 200 μl ORIGEN assay buffer (Igen, Inc., Gaithersburg, Md.)is then added and the extent of receptor association measured using anM8 ORIGEN analyzer (Igen, Inc.).

Example 17 Construct for Generating a Zcytor17 Receptor Heterodimer

A vector expressing a secreted human zcytor17 heterodimer isconstructed. In this construct, the extracellular cytokine-bindingdomain of zcytor17 is fused to the heavy chain of IgG gamma 1 (IgGγ1)(SEQ ID NO:37 and SEQ ID NO:38), while the extracellular portion of theheteromeric cytokine receptor subunit (E.g., an gp130, LIF, IL-12,WSX-1, or IL-2 receptor component (IL-2Rα, IL-2Rβ, IL-2Rγ), anIL-4/IL-13 receptor family receptor components (IL-4Rα, IL-13Rα,IL-13Rα′), interleukin receptor subunits (e.g., IL-15 Rα, IL-7Rα,IL-9Rα); or zalpha11 receptor (IL-21R)) is fused to a human kappa lightchain (human κ light chain) (SEQ ID NO:39 and SEQ ID NO:40).

A. Construction of IgG Gamma 1 and Human κ Light Chain Fusion Vectors

The heavy chain of IgGγ1 (SEQ ID NO:37) is cloned into the Zem229Rmammalian expression vector (ATCC deposit No. 69447) such that anydesired cytokine receptor extracellular domain having a 5′ EcoRI and 3′NheI site can be cloned in resulting in an N-terminal extracellulardomain-C-terminal IgGγ1 fusion. The IgGγ1 fragment used in thisconstruct is made by using PCR to isolate the IgGγ1 sequence from aClontech hFetal Liver cDNA library as a template. PCR products arepurified using methods described herein and digested with MluI and EcoRI(Boerhinger-Mannheim), ethanol precipitated and ligated with oligosZC11,440 (SEQ ID NO:41) and ZC11,441 (SEQ ID NO:42), which comprise anMluI/EcoRI linker, into Zem229R previously digested with and EcoRI usingstandard molecular biology techniques disclosed herein.

The human κ light chain (SEQ ID NO:39) is cloned in the Zem228Rmammalian expression vector (ATCC deposit No. 69446) such that anydesired cytokine receptor extracellular domain having a 5′ EcoRI siteand a 3′ KpnI site can be cloned in resulting in a N-terminal cytokineextracellular domain-C-terminal human κ light chain fusion. As a KpnIsite is located within the human κ light chain sequence (cleaved by theKpnI enzyme after nucleotide 62 in SEQ ID NO:39), a special primer isdesigned to clone the 3′ end of the desired extracellular domain of acytokine receptor into this KpnI site: The primer is designed so thatthe resulting PCR product contains the desired cytokine receptorextracellular domain with a segment of the human κ light chain up to theKpnI site (SEQ ID NO:39). This primer preferably comprises a portion ofat least 10 nucleotides of the 3′ end of the desired cytokine receptorextracellular domain fused in frame 5′ to SEQ ID NO:39. The human κlight chain fragment used in this construct is made by using PCR toisolate the human κ light chain sequence from the same Clontech humanFetal Liver cDNA library used above. PCR products are purified usingmethods described herein and digested with MluI and EcoRI(Boerhinger-Mannheim), ethanol precipitated and ligated with theMluI/EcoRI linker described above, into Zem228R previously digested withand EcoRI using standard molecular biology techniques disclosed herein.

B. Insertion of Zcytor17 Receptor or Heterodimeric Subunit ExtracellularDomains into Fusion Vector Constructs

Using the construction vectors above, a construct having zcytor17 fusedto IgGγ1 is made. This construction is done by PCRing the extracellulardomain or cytokine-binding domain of zcytor17 receptor described hereinfrom a prostate cDNA library (Clontech) or activated lymphocyte cDNAlibrary using standard methods (E.g., Example 7), and oligos thatprovide EcoRI and NheI restriction sites. The resulting PCR product isdigested with EcoRI and NheI, gel purified, as described herein, andligated into a previously EcoRI and NheI digested and band-purifiedZem229R/IgGγ1 described above. The resulting vector is sequenced toconfirm that the zcytor17/IgG gamma 1 fusion (zcytor17/Ch1 IgG) iscorrect.

A separate construct having a heterodimeric cytokine receptor subunitextracellular domain fused to κ K light is also constructed as above.The cytokine receptor/human κ light chain construction is performed asabove by PCRing from, e.g., a lymphocyte cDNA library (Clontech) usingstandard methods, and oligos that provide EcoRI and KpnI restrictionsites. The resulting PCR product is digested with EcoRI and KpnI andthen ligating this product into a previously EcoRI and KpnI digested andband-purified Zem228R/human κ light chain vector described above. Theresulting vector is sequenced to confirm that the cytokine receptorsubunit/human κ light chain fusion is correct.

D. Co-Expression of the Zcytor17 and Heterodimeric Cytokine ReceptorSubunit Extracellular Domain

Approximately 15 μg of each of vectors above, are co-transfected intomammalian cells, e.g., BHK-570 cells (ATCC No. CRL-10314) usingLipofectaminePlus™ reagent (Gibco/BRL), as per manufacturer'sinstructions. The transfected cells are selected for 10 days in DMEM+5%FBS (Gibco/BRL) containing 1 μM of methotrexate (MTX) (Sigma, St.Louis, Mo.) and 0.5 mg/ml G418 (Gibco/BRL) for 10 days. The resultingpool of transfectants is selected again in 10 μm of MTX and 0.5 mg/mlG418 for 10 days.

The resulting pool of doubly selected cells is used to generate protein.Three Factories (Nunc, Denmark) of this pool are used to generate 10 Lof serum free conditioned medium. This conditioned media is passed overa 1 ml protein-A column and eluted in about 10,750 microliter fractions.The fractions having the highest protein concentration are pooled anddialyzed (10 kD MW cutoff) against PBS. Finally the dialyzed material issubmitted for amino acid analysis (AAA) using routine methods.

Example 18 Determination of Receptor Subunits That Heterodimerize orMultimerize With Zcytor17 Receptor

Using standard methods described herein, The BaF3/MPL-zcytor17 chimeracells (Example 6) are transfected with an additional heterodimericcytokine receptor subunit serve as a bioassay cell line to measuresignal transduction response of heterodimeric zcytor17 receptorcomplexes to the luciferase reporter in the presence of TPO (Example 6).Transfection of the BaF3/MPL-zcytor17 cell line with and additionalMPL-class I cytokine receptor fusion that signals in the presence of theTPO ligand, determines which heterodimeric cytokine receptor subunitsare required for zcytor17 receptor signaling. Use of MPL-receptorfusions for this purpose alleviates the requirement for the presence ofa natural ligand for the zcytor17 receptor.

MPL-class I cytokine receptor fusions are made as per Example 5 usingthe extracellular domain and transmembrane domains of the MPL receptorand the intracellular signaling domain of the desired class I cytokinereceptor. The BaF3/MPL-zcytor17 bioassay cell line co-transfected withan individual MPL-class I cytokine receptor fusions as per Example 6 toform a BaF3/MPL-zcytor17/MPL-class I cytokine receptor cell line.Receptor complexes include but are not limited to zcytor17 receptor incombination with an MPL-cytokine receptor fusion comprising a gp130,LIF, IL-12, or WSX-1 component, or one or more of the IL-2 receptorcomponents (IL-2Rα, IL-2Rβ, IL-2Rγ), zcytor17 receptor with one or moreof the IL-4/IL-13 receptor family receptor components (IL-4Rα, IL-13Rα,IL-13Rα′), as well as other Interleukin receptors (e.g., IL-15 Rα,IL-7Rα, IL-9Rα, IL-21R (Zalpha11 receptor)). Each independent receptorcomplex cell line is then assayed in the presence of TPO (example 6) andproliferation measured using routine methods (e.g., Alamar Blue assay asdescribed in Example 6). The BaF3/MPL-zcytor17 bioassay cell line servesas a control for the background activity, and is thus used as a baselineto compare signaling by the various receptor complex combinations.Moreover, assay by luciferase reporter assay (activation oftranscription of a reporter gene) can also be used as a way to measuresignaling regardless of induction of proliferation. In addition, aBaF3/MPL-class I cytokine receptor cell line can be constructed tocontrol for MPL-class I cytokine receptor homodimerization effects forthose class I cytokine receptors known to signal upon homodimerization.The TPO in the presence of the correct receptor complex, is expected toincrease proliferation of the BaF3/MPL-zcytor17/MPL-class I cytokinereceptor cell line approximately 5 fold over background or greater inthe presence of TPO.

Example 19 Reconstitution of Zcytor17 Receptor in Vitro

To identify components involved in the zcytor17-signaling complex,receptor reconstitution studies are performed as follows. For example,BHK 570 cells (ATCC No. CRL-10314) transfected, using standard methodsdescribed herein, with a luciferase reporter mammalian expression vectorplasmid serve as a bioassay cell line to measure signal transductionresponse from a transfected zcytor17 receptor complex to the luciferasereporter in the presence of zcytor17 Ligand. BHK cells would be used inthe event that BHK cells do not endogenously express the zcytor17receptor. Other cell lines can be used. An exemplary luciferase reportermammalian expression vector is the KZ134 plasmid which is constructedwith complementary oligonucleotides ZC12,749 (SEQ ID NO:43) and ZC12,748(SEQ ID NO:44) that contain STAT transcription factor binding elementsfrom 4 genes. A modified c-fos Sis inducible element (m67SIE, or hSIE)(Sadowski, H. et al., Science 261:1739-1744, 1993), the p21 WAF1 fromthe p21 WAF1 gene (Chin, Y. et al., Science 272:719-722, 1996), themammary gland response element of the β-casein gene (Schmitt-Ney, M. etal., Mol. Cell. Biol. 11:3745-3755, 1991), and a STAT inducible elementof the Fcg RI gene, (Seidel, H. et al., Proc. Natl. Acad. Sci.92:3041-3045, 1995). These oligonucleotides contain Asp718-XhoIcompatible ends and are ligated, using standard methods, into arecipient firefly luciferase reporter vector with a c-Fos promoter(Poulsen, L. K. et al., J. Biol. Chem. 273:6229-6232, 1998) digestedwith the same enzymes and containing a neomycin selectable marker. TheKZ134 plasmid is used to stably transfect BHK, or BaF3 cells, usingstandard transfection and selection methods, to make a BHK/KZ134 orBaF3/KZ134 cell line respectively.

The bioassay cell line is transfected with zcytor17 receptor alone, orco-transfected with zcytor17 receptor along with one of a variety ofother known receptor subunits. Receptor complexes include but are notlimited to zcytor17 receptor only, various combinations of zcytor17receptor with gp130, LIF, IL-12, or WSX-1 receptor subunits, or one ormore of the IL-2 receptor components (IL-2Rα, IL-2Rβ, IL-2Rγ), zcytor17receptor with one or more of the IL-4/IL-13 receptor family receptorcomponents (IL-4Rα, IL-13Rα, IL-13Rα′), as well as other Interleukinreceptors (e.g., IL-15 Rα, IL-7Rα, IL-9Rα, IL-21R (zalpha11)). Eachindependent receptor complex cell line is then assayed in the presenceof cytokine-conditioned media or purified cytokines and luciferaseactivity measured using routine methods. The untransfected bioassay cellline serves as a control for the background luciferase activity, and isthus used as a baseline to compare signaling by the various receptorcomplex combinations. The conditioned medium or cytokine that binds thezcytor17 receptor in the presence of the correct receptor complex, isexpected to give a luciferase readout of approximately 5 fold overbackground or greater.

As an alternative, a similar assay can be performed wherein theBaf3/zcytor17-mp1 and Baf3/zcytor17 (Example 10) cell lines areco-transfected as described above and proliferation measured.

Example 20 Construction of BaF3 Cells Expressing Full-Length Zcytor17

BaF3, an interleukin-3 (IL-3) dependent prelymphoid cell line derivedfrom murine bone marrow (Palacios and Steinmetz, Cell 41: 727-734, 1985;Mathey-Prevot et al., Mol. Cell. Biol. 6.: 4133-4135, 1986), wasmaintained in complete media (RPMI medium (JRH Bioscience Inc., Lenexa,Kans.) supplemented with 10% heat-inactivated fetal calf serum, 2 ng/mlmurine IL-3 (mIL-3) (R+D, Minneapolis, Minn.), 2 mM L-glutamine(Gibco-BRL), and 1 mM Sodium Pyruvate (Gibco-BRL).

BaF3 cells for electroporation were washed twice in PBS, pH 7.2(Gibco-BRL) and then resuspended in PBS and a cell density of 10⁷cells/ml. One ml of resuspended BaF3 cells was mixed with 30 μg of thepZP7PX/zcytor17 plasmid DNA and transferred to separate disposableelectroporation chambers (Gibco-BRL). The cells were then given 2 serialshocks (800 IFad/300V.; 1180 1Fad/300V.) delivered by an electroporationapparatus (CELL-PORATOR™; Gibco-BRL). The electroporated cells were thentransferred to 20 mls of complete media and placed in an incubator for48 hours (37° C., 5% CO₂). The cells were then spun down and resuspendedin 20 mls of complete media containing 2 μg/ml Puromycin (ClonTech)Selection in a T75 flask to isolate the puromycin resistant pool. Clonallines of the transfected BaF3 cells, hereinafter called BaF3/zcytor17cells, were isolated as described below.

BaF3/zcytor17 cells were counted in a hemocytometer, and plated at 1cell/well, 0.5 cell/well, 0.1 cell/well, and 0.01 cell/well, in a volumeof 100 μl/well in complete media containing 2 μg/ml Puromycin. 15 cloneswere scaled up to T75 flasks, and 5 clones were assayed for RNAproduction. Cells were washed once with PBS and counted with ahemocytometer. 5×10⁶ cells were spun down and the media removed.Untransfected BaF3 cells were also counted and pelleted. Four of thepellets were frozen at −80° C. overnight. RNA was isolated using theS.N.A.P.™ Total RNA Isolation Kit (Invitrogen) as per manufacturer'sinstructions, and total RNA yield was determined by spectrophotometer.The amount of zcytor17 RNA was then determined by RT-PCR using theRT-PCR Kit (Stratagene) as per manufacturer's instructions, usingzcytor17-specific primers ZC29,180 (SEQ ID NO:72) and ZC29,122 (SEQ IDNO:65). One clone that gave a strong band of zcytor17 RNA was selectedto use in BaF3 Alamar Blue proliferation assays (Example 6) to testpotential ligands.

Example 21 Cloning of Mouse ZcytoR17 From a Mouse Testes cDNA Library

A mouse testes cDNA library was screened for a full-length clone ofmouse zcytoR17. The library was plated at 65,500 cfu/plate on 24 LB+Ampplates. Filter lifts were prepared using Hybond N (Amersham-PharmaciaBiotech, Inc., Piscataway, N.J.) on a total of approximately 1.6 millioncolonies. The filters were marked with a hot needle for orientation andthen denatured for 6 minutes in 0.5 M NaOH and 1.5 M Tris-HCl, pH 7.2.The filters were then neutralized in 1.5 M NaCl and 0.5 M Tris-HCl, pH7.2 for 6 minutes. The DNA was affixed to the filters using a UVcrosslinker (Stratalinker®, Stratagene, La Jolla, Calif.) at 1200joules. The filters were then left to dry overnight at room temperature.

The next day, the filters were pre-washed at 65° C. in pre-wash bufferconsisting of 0.25×SSC, 0.25% SDS and 1 mM EDTA. Cell debris wasmanually removed using Kimwipes® (Kimberly-Clark) and the solution waschanged 3 times over a period of 1 hour. Filters were air dried andstored at room temperature until needed. The filters were thenprehybridized for approximately 3 hours at 63° C. in 20 ml ofExpressHyb™Hybridization Solution (Clontech, Palo Alto, Calif.).

Probe B (Example 3C) was generated by PCR from human zcytoR17 templateusing oligonucleotide primers ZC27,895 (SEQ ID NO:64) and ZC28,917 (SEQID NO:73) and was radioactively labeled with ³²P using a commerciallyavailable kit (Megaprime DNA Labeling System; Amersham PharmaciaBiotech, Piscataway, N.J.) according to the manufacturer's instructions.The probe was purified using a Stratagene™ push column (NucTrap® column;Stratagene, La Jolla, Calif.). The probe was denatured at 100° C. for 15min and added to ExpressHyb™. Filters were hybridized in 15 mlhybridizing solution containing 1.6×10⁶ cpm/ml of probe at 63° C.overnight. Filters were washed at 55° C. in 2×SSC, 0.1% SDS and 1 mMEDTA and exposed to X-ray film at −80° C. for 4½ days. Thirteenpositives were picked from the plates as plugs and placed in 1 ml LB+ampin 1.7 ml tubes. Tubes were placed at 4° C. overnight. These 13positives were subjected to two further rounds of purification. Thetertiary plates were outgrown at 37° C. after filter lifts were takenand single colonies were picked and sent to sequencing. Three of thesewere determined to contain sequence of the mouse ortholog of zcytoR17.

In addition, a PCR product was generated using CTLL-2 cDNA as a templateand oligonucleotides ZC38,239 (SEQ ID NO:88) and ZC38,245 (SEQ ID NO:89)as primers. CTLL-2 is a mouse cytotoxic T lymphocyte cell line (ATCC No.TIB-214). This PCR reaction was run as follows: 1 cycle at 95° C. for 1minute, 30 cycles at 95° C. for 15 seconds, 68° C. for 3 minutes, then68° C. for 10 minutes; 4° C. soak. The PCR reaction used approximately0.5 ng. of cDNA, 20 pmoles of each oligonucleotide, and 1 μl. ofAdvantage II polymerase mix (ClonTech). About 6% of the PCR product wasused as a template in a new PCR reaction, as above, except witholigonucleotides ZC38,239 (SEQ ID NO:88) and ZC38,238 (SEQ ID NO:90).This PCR reaction was run as follows: 30 cycles at 94° C. for 45seconds, 65° C. for 45 seconds, 72° C. for 1 minute, then 72° C for 7minutes; 10°C. soak. Most of the PCR reaction was loaded on a 1.0%agarose gel and the predominant band at approximately 360 bp wasexcised, the DNA fragment was eluted, and DNA sequencing was performed.

The sequence of the mouse zcytor17 polynucleotide is shown in SEQ IDNO:56 and the corresponding amino acid sequence shown in SEQ ID NO:57.In addition, a truncated soluble form of the mouse zcytor17polynucleotide is shown in SEQ ID NO:92 and the corresponding amino acidsequence shown in SEQ ID NO:93.

Example 22 Tissue Distribution of Human Zcytor17 in Tissue Panels UsingPCR

A panel of cDNAs from murine tissues was screened for mouse zcytor17expression using PCR. The panel was made in-house and contained 94marathon cDNA and cDNA samples from various normal and cancerous murinetissues and cell lines are shown in Table 7, below. The cDNAs came fromin-house libraries or marathon cDNAs from in-house RNA preps, ClontechRNA, or Invitrogen RNA. The mouse marathon cDNAs were made sing themarathon-Ready™ kit (Clontech, Palo Alto, Calif.) and QC tested withmouse transferrin receptor primers ZC10,651 (SEQ ID NO:79) and ZC10,565(SEQ ID NO:80) and then diluted based on the intensity of thetransferrin band. To assure quality of the amplified library samples inthe panel, three tests for quality control (QC) were run: (1) To assessthe RNA quality used for the libraries, the in-house cDNAs were testedfor average insert size by PCR with vector oligos that were specific forthe vector sequences for an individual cDNA library; (2) Standardizationof the concentration of the cDNA in panel samples was achieved usingstandard PCR methods to amplify full length alpha tubulin or G3PDH cDNAusing a 5′ vector oligo: ZC14,063 (SEQ ID NO:7) and 3′ alpha tubulinspecific oligo primer ZC17,574 (SEQ ID NO:26) or 3′ G3PDH specific oligoprimer ZC17,600 (SEQ ID NO:27); and (3) a sample was sent to sequencingto check for possible ribosomal or mitochondrial DNA contamination. Thepanel was set up in a 96-well format that included a mouse genomic DNA(Clontech, Palo Alto, Calif.) positive control sample. Each wellcontained approximately 0.2-100 pg/μl of cDNA. The PCR was set up usingoligos ZC38,065 (SEQ ID NO:77) and ZC38,068 (SEQ ID NO:78), TaKaRa ExTaq™ (TAKARA Shuzo Co LTD, Biomedicals Group, Japan), and Rediload dye(Research Genetics, Inc., Huntsville, Al.). The amplification wascarried out as follows: 1 cycle at 94° C. for 5 minutes; 5 cycles of 94°C. for 30 seconds, 68° C. for 30 seconds; 35 cycles of 94° C. for 30seconds, 56° C. for 30 seconds and 72° C. for 30 seconds, followed by 1cycle at 72° C. for 5 minutes. About 10 μl of the PCR reaction productwas subjected to standard Agarose gel electrophoresis using a 4% agarosegel. The correct predicted DNA fragment size was observed in brain,CD90+ cells, dendritic, embryo, MEWt#2, Tuvak-prostate cell line,salivary gland, skin and testis.

The DNA fragment for skin and testis were excised and purified using aGel Extraction Kit (Qiagen, Chatsworth, Calif.) according tomanufacturer's instructions. Fragments were confirmed by sequencing toshow that they were indeed mouse zcytor17. TABLE 7 Tissue/Cell line#samples Tissue/Cell line #samples 229 1 7F2 1 Adipocytes-Amplified 1aTC1.9 1 Brain 4 CCC4 1 CD90+ Amplified 1 OC10B 1 Dentritic 1 Embyro 1Heart 2 Kidney 3 Liver 2 Lung 2 MEWt#2 1 P388D1 1 Pancreas 1 Placenta 2Jakotay-Prostate Cell Line 1 Nelix-Prostate Cell Line 1 Paris-ProstateCell Line 1 Torres-Prostate Cell Line 1 Tuvak-Prostate Cell Line 1Salivary Gland 2 Skeletal Muscle 1 Skin 2 Small Intestine 1 SmoothMuscle 2 Spleen 2 Stomach 1 Testis 3 Thymus 1

Example 23 Zcytor17 Expression in Various Tissues Using Real-TimeQuantitative RT/PCR

A. Primers and Probes for Quantitative RT-PCR

Real-time quantitative RT-PCR using the ABI PRISM 7700 SequenceDetection System (PE Applied Biosystems, Inc., Foster City, Calif.) hasbeen previously described (See, Heid, C. A. et al., Genome Research6:986-994, 1996; Gibson, U.E.M. et al., Genome Research 6:995-1001,1996; Sundaresan, S. et al., Endocrinology 139:4756-4764, 1998. Thismethod incorporates use of a gene specific probe containing bothreporter and quencher fluorescent dyes. When the probe is intact thereporter dye emission is negated due to the close proximity of thequencher dye. During PCR extension using additional gene-specificforward and reverse primers, the probe is cleaved by 5′ nucleaseactivity of Taq polymerase which releases the reporter dye from theprobe resulting in an increase in fluorescent emission.

The primers and probes used for real-time quantitative RT-PCR analysesof Zcytor17 expression were designed using the primer design softwarePrimer Express™ (PE Applied Biosystems, Foster City, Calif.). Primersfor human Zcytor17 were designed spanning an intron-exon junction toeliminate amplification of genomic DNA. The forward primer, ZC37,877(SEQ ID NO:81) and the reverse primer, ZC37,876 (SEQ ID NO:82) were usedin a PCR reaction (below) at about 300 nM concentration to synthesize a73 bp product. The corresponding Zcytor17 TaqMan® probe, designatedZG37,776 (SEQ ID NO:83) was synthesized and labeled by PE AppliedBiosystems. The ZG37,776 probe was labeled at the 5′ end with a reporterfluorescent dye (6-carboxy-fluorescein) (FAM) (PE Applied Biosystems)and at the 3′ end with a quencher fluorescent dye(6-carboxy-tetramethyl-rhodamine) (TAMRA) (PE Applied Biosystems).

As a control to test the integrity and quality of RNA samples tested,all RNA samples (below) were screened for rRNA using a primer and probeset ordered from PE Applied Biosystems (cat# 4304483). The kit containsthe rRNA forward primer (SEQ ID NO:84), the rRNA reverse primer (SEQ IDNO:85), and the rRNA TaqMan® probe (SEQ ID NO:86) The rRNA probe waslabeled at the 5′ end with a reporter fluorescent dye VIC (PE AppliedBiosystems) and at the 3′ end with the quencher fluorescent dye TAMRA(PE Applied Biosystems). The rRNA results also serve as an endogenouscontrol and allow for the normalization of the Zcytor17 mRNA expressionresults seen in the test samples.

Blood was drawn from several anonymous donors and PBMC's isolated.Various immune cell subsets (CD3+, CD4+, CD8+, CD14+, CD19+, CD45RA,CD45RO and CD56+) were then isolated using Microbeads and the MagneticCell Separation System from Miltenyi Biotec. RNA was prepared from allof the CD45RA, CD45RO and CD56+populations in their resting state usingan RNeasy Midiprep™ Kit (Qiagen, Valencia, Calif.) as per manufacturer'sinstruction. The CD3+, CD4+, and CD8+ populations were activated using200 ng/ml plate-bound anti-CD3 antibody and 5 ug/ml soluble anti-CD28antibody and cells were collected for RNA isolation at 0, 4 and 16hours. The CD19+ samples were isolated from human tonsil and activatedwith 0.5 ug/ml ionomycin and 10 ng/ml PMA. Cells were then collected at0, 4 hours and 24 hours and RNA isolated. Human CD 14+ monocytes wereactivated with either 0.1 ug/ml LPS or 1.0 ug/ml LPS for 20 hours.Resting and activated cells were then collected and RNA isolated. Inaddition, RNA was isolated from resting and activated (10.0 ug/ml LPS)human monocyte cell lines HL-60, THP-1 (ATCC No. TIB-202) and U937.THP-1 RNA was used as a control because it was shown to express Zcytor17by Northern Blot (Example 3).

B. Real-Time quantitative RT-PCR

Relative levels of Zcytor17 mRNA were determined by analyzing total RNAsamples using the one-step RT-PCR method (PE Applied Biosystems). TotalRNA from Zcytor17 expressing THP-1 cells was isolated by standardmethods and used to generate a standard curve used for quantitation. Thecurve consisted of 10-fold serial dilutions ranging from0.25-0.00025ng/μl for the rRNA screen and 250-0.25 ng/μl for theZcytor17 screen with each standard curve point analyzed in triplicate.The total RNA samples from the human cells were also analyzed intriplicate for human Zcytor17 transcript levels and for levels of rRNAas an endogenous control. In a total volume of 25 μl, each RNA samplewas subjected to a One-Step RT-PCR reaction containing: approximately 50ng of total RNA in buffer A (50 mM KCL, 10 mM Tris-HCL); the internalstandard dye, carboxy-x-rhodamine (ROX)); appropriate primers(approximately 50 nM rRNA primers (SEQ ID NO:84 and SEQ ID NO:85) forthe rRNA samples; and approximately 300 nM ZC37,877 (SEQ ID NO:81) andZC22,276 (SEQ ID NO:87) primers for Zcytor17 samples); the appropriateprobe (approximately 50 nM rRNA TaqMan® probe (SEQ ID NO:86) for rRNAsamples, approximately 100 nM ZG37,776 (SEQ ID NO:83) probe for Zcytor17samples); 5.5 mM MgCl₂; 300 μM each d-CTP, d-ATP, and d-GTP and 600 μMof d-UTP; MuLV reverse transcriptase (0.25 U/μl); AmpliTaq™ Gold DNApolymerase (0.025 U/μl) (PE Applied Biosystems); and RNase Inhibitor(0.4 U/μl) (PE Applied Biosystems). PCR thermal cycling conditions wereas follows: an initial reverse transcription (RT) step of one cycle at48° C. for 30 minutes; followed by an AmpliTaq Gold™ (PE AppliedBiosystems) activation step of one cycle at 95° C. for 10 minutes;followed by 40 cycles of amplification at 95° C. for 15 second and 60°C. for 1 minute.

Relative Zcytor17 RNA levels were determined by using the Standard CurveMethod as described by the manufacturer, PE Biosystems (User Bulletin#2: ABI Prism 7700 Sequence Detection System, Relative Quantitation ofGene Expression, Dec. 11, 1997). The rRNA measurements were used tonormalize the Zcytor17 levels. Three experiments were done testing theaforementioned. Data shown in Tables 8 and 9 below are expressed as aratio of Zcytor17 mRNA to rRNA. TABLE 8 16 hr 24 hr Sample Resting 4 hrStimulation Stimulation Stimulation CD19+ PBMC 0.06 CD19+ Tonsil 0.0030.02 .002 CD3+ 0 0.72 0.51 CD45RA 0 CD45RO 0 CD56+ NK 0

TABLE 9 16 hr Sample Resting 4 hr Stimulation Stimulation CD4+ T Cell0.003 0.55 0.41 CD8+ T Cell 0.00 0.37 0.13

While there was some expression of Zcytor17 message in resting CD19+ Bcells from the peripheral blood, both resting and activated CD19+ Bcells isolated from human tonsil showed only minimal expression. Restingmemory T cells (CD45RO), naïve T Cells (CD45RA) and NK cells (CD56+) alltested negative for Zcytor17 message. However, in CD3+ T cells, Zcytor17message underwent a dramatic upregulation to a ratio of about 0.72following a 4 hour activation with anti-CD3 and anti-CD28 antibodies.The ratio then dropped to 0.51 by 16 hours post-activation. Prior toactivation, no Zcytor17 mRNA was detected in resting CD3+ T cells.

The results revealed that Zcytor17 was not present in appreciable levelsin resting CD4+ or CD8+ T cell subsets. Following a 4 hour activationwith anti-CD3 and anti-CD28 antibodies there appears to be a substantialupregulation of Zcytor17 message produced in both CD4+ and CD8+ T cellsubsets. By 16 hours post-activation, the Zcytor17 mRNA had decreased to0.41 in CD4+ T cells and 0.13 in CD8+ T cells.

There was extremely high expression of Zcytor17 message in both theresting and activated monocyte cell lines THP-1 and U937. The activatedU937's have the highest level of expression. HL-60's, apre-differentiated monocyte cell line, showed a decrease in Zcytor17mRNA expression upon activation. These results support expressionresults done by northern blot (Example 2). There was very littleexpression of Zcytor17 message in primary CD 14+ monocytes both restingand activated with 0.1 ug/ml and 1.0 ug/ml LPS.

From the foregoing, it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. An isolated polynucleotide encoding a polypeptide, wherein theencoded polypeptide comprises a sequence of amino acid residues that isselected from the group consisting of: (a) the amino acid sequence asshown in SEQ ID NO:2 from amino acid number 20 (Ala) to amino acidnumber 227 (Pro); (b) the amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to amino acid number 519 (Glu); (c) theamino acid sequence as shown in SEQ ID NO:2 from amino acid number 20(Ala) to amino acid number 543 (Leu); (d) the amino acid sequence asshown in SEQ ID NO:2 from amino acid number 544 (Lys) to amino acidnumber 732 (Val); (e) the amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to amino acid number 732 (Val); and (f)the amino acid sequence as shown in SEQ ID NO:2 from amino acid number 1(Met) to amino acid number 732 (Val).
 2. An isolated polynucleotidecomprising a sequence selected from the group consisting of: (a) apolynucleotide as shown in SEQ ID NO:1 from nucleotide number 228 toamino acid number 851; (b) a polynucleotide as shown in SEQ ID NO:1 fromnucleotide number 228 to amino acid number 1727; (c) a polynucleotide asshown in SEQ ID NO:1 from nucleotide number 228 to amino acid number1799; (d) a polynucleotide as shown in SEQ ID NO:1 from nucleotidenumber 1800 to amino acid number 2366; (e) a polynucleotide as shown inSEQ ID NO:1 from nucleotide number 228 to amino acid number 2366; (f) apolynucleotide as shown in SEQ ID NO:1 from nucleotide number 171 toamino acid number 2366; and (g) a polynucleotide sequence complementaryto (a) through (f).
 3. An isolated polynucleotide according to claim 1,wherein the encoded polypeptide has activity as measured by cellproliferation, activation of transcription of a reporter gene, orwherein the encoded polypeptide further binds to an antibody, whereinthe antibody is raised to a polypeptide comprising a sequence of aminoacids selected from the group consisting of: (a) the polypeptidecomprising amino acid number 20 (Ala) to 227 (Pro) of SEQ ID NO:2; (b)the polypeptide comprising amino acid number 20 (Ala) to 519 (Glu) ofSEQ ID NO:2; (c) the polypeptide comprising amino acid number 20 (Ala)to 543 (Leu) of SEQ ID NO:2; (d) the polypeptide comprising amino acidnumber 544 (Lys) to 732 (Val) of SEQ ID NO:2; (e) the polypeptidecomprising amino acid number 20 (Ala) to 732 (Val) of SEQ ID NO:2; and(f) the polypeptide comprising amino acid number 1 (Met) to 732 (Val) ofSEQ ID NO:2; and wherein the binding of the antibody to the isolatedpolypeptide is measured by a biological or biochemical assay includingradioimmunoassay, radioimmuno-precipitation, Western blot, orenzyme-linked immunosorbent assay.
 4. An expression vector comprisingthe following operably linked elements: a transcription promoter; a DNAsegment encoding a polypeptide comprising an amino acid sequence asshown in SEQ ID NO:2 from amino acid number 20 (Ala) to 732 (Val); and atranscription terminator, wherein the promoter is operably linked to theDNA segment, and the DNA segment is operably linked to the transcriptionterminator.
 5. An expression vector according to claim 4, furthercomprising a secretory signal sequence operably linked to the DNAsegment.
 6. A cultured cell comprising an expression vector according toclaim 4, wherein the cell expresses a polypeptide encoded by the DNAsegment.
 7. An expression vector comprising the following operablylinked elements: a transcription promoter; a DNA segment encoding apolypeptide comprising an amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to 227 (Pro); or as shown in SEQ ID NO:2from amino acid number 20 (Ala) to 519 (Glu); and a transcriptionterminator, wherein the promoter, DNA segment, and terminator areoperably linked.
 8. An expression vector according to claim 7, furthercomprising a secretory signal sequence operably linked to the DNAsegment.
 9. An expression vector according to claim 7, wherein thepolypeptide further comprises a transmembrane domain consisting ofresidues 520 (Ile) to 543 (Leu) of SEQ ID NO:2.
 10. An expression vectoraccording to claim 7 wherein the polypeptide further comprises anintracellular domain consisting of residues 544 (Lys) to 732 (Val) ofSEQ ID NO:2.
 11. A cultured cell into which has been introduced anexpression vector according to claim 7, wherein the cell expresses asoluble receptor polypeptide encoded by the DNA segment.
 12. A DNAconstruct encoding a fusion protein, the DNA construct comprising: afirst DNA segment encoding a polypeptide comprising a sequence of aminoacid residues selected from the group consisting of: (a) the amino acidsequence of SEQ ID NO:2 from amino acid number 1 (Met), to amino acidnumber 19 (Ala); (b) the amino acid sequence of SEQ ID NO:2 from aminoacid number 20 (Ala), to amino acid number 227 (Pro); (c) the amino acidsequence of SEQ ID NO:2 from amino acid number 20 (Ala), to amino acidnumber 519 (Glu); (d) the amino acid sequence as shown in SEQ ID NO:2from amino acid number 20 (Ala) to amino acid number 543 (Leu); (e) theamino acid sequence as shown in SEQ ID NO:2 from amino acid number 520(Ile) to amino acid number 543 (Leu); (f) the amino acid sequence asshown in SEQ ID NO:2 from amino acid number 544 (Lys) to amino acidnumber 732 (Val); and (g) the amino acid sequence as shown in SEQ IDNO:2 from amino acid number 20 (Ala) to amino acid number 732 (Val); andat least one other DNA segment encoding an additional polypeptide,wherein the first and other DNA segments are connected in-frame; andwherein the first and other DNA segments encode the fusion protein. 13.An expression vector comprising the following operably linked elements:a transcription promoter; a DNA construct encoding a fusion proteinaccording to claim 12; and a transcription terminator, wherein thepromoter is operably linked to the DNA construct, and the DNA constructis operably linked to the transcription terminator.
 14. A cultured cellcomprising an expression vector according to claim 13, wherein the cellexpresses the fusion protein encoded by the DNA construct.
 15. A methodof producing a fusion protein comprising: culturing a cell according toclaim 14; and isolating the fusion protein produced by the cell.
 16. Amethod of producing a polypeptide comprising: culturing a cell accordingto claim 11; and isolating the polypeptide produced by the cell.
 17. Anisolated soluble receptor polypeptide comprising amino acid residues20-519 of SEQ ID NO:2.
 18. The isolated soluble receptor polypeptide ofclaim 17 wherein the isolated soluble receptor polypeptide is fused toan immunoglobulin heavy chain constant region.
 19. The isolated solublereceptor polypeptide of claim 18 wherein the immunoglobulin heavy chainconstant region is a human immunoglobulin F_(c)4 fragment.
 20. Anisolated polypeptide comprising amino acid residues 20-732 of SEQ IDNO:2.
 21. An isolated polynucleotide encoding a soluble receptorpolypeptide wherein the soluble receptor polypeptide comprises aminoacid residues 20-519 of SEQ ID NO:2.
 22. The isolated polynucleotide ofclaim 21 wherein the soluble receptor polypeptide is fused to animmunoglobulin heavy chain constant region.
 23. The isolatedpolynucleotide of claim 22 wherein wherein the immunoglobulin heavychain constant region is a human immunoglobulin F_(c)4 fragment.
 24. Anexpression vector comprising the following operably linked elements: atranscription promoter; a DNA segment encoding a soluble receptorpolypeptide comprising amino acid residues 20-519 of SEQ ID NO:2; and atranscription terminator, wherein the promoter is operably linked to theDNA segment, and the DNA segment is operably linked to the transcriptionterminator.
 25. The expression vector of claim 24 further comprising asecretory signal sequence operably linked to the DNA segment.
 26. Theexpression vector of claim 24 further comprising an immunoglobulin heavychain constant region operably linked to the DNA segment.
 27. Theexpression vector of claim 26 wherein the immunoglobulin heavy chainconstant region is a human immunoglobulin F_(c)4 fragment.
 28. Acultured cell comprising an expression vector according to claim 24,wherein the cell expresses the soluble receptor polypeptide encoded bythe DNA segment.